Murray directs a few tennis balls into the crowd before leaving the court, which means it's time for us to wrap things up. If you want to read the match report of Murray's match click here. All the latest results are on our, well, results page. Thanks for joining us.
Post update
Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"Andy Murray's focus looks really good. He doesn't look like's he's got much stress, but he's got the 'grrrr' if he needs it. He looks mentally fresh and ready to go. There's not really much pressure on him because he's not the one everyone is talking about to win the tournament."
"Nick Kyrgios can hold his head up pretty high after that match. He has shown the potential he has got tonight. Andy Murray is looking in great shape and it's exciting to see how he moves through this tournament."
Day 3 schedule
Wednesday's order of play has been announced and the night matches (from 00:00 BST) will involve Venus Williams and Novak Djokovic.
Arthur Ashe Stadium
Madison Keys (USA) v Tereza Smitkova
Marin Cilic (Cro) v Evgeny Donskoy (Rus)
Serena Williams (USA) v Kiki Bertens (Ned)
Irina Falconi (USA) v Venus Williams (USA)
Novak Djokovic (SRB) V Andreas Haider-Maurer
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David Law
BBC Radio 5 live commentator
"There were flashes of brilliance from Kyrgios - there was the usual Kyrgios show. But Andy Murray coped with all that."
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"Obviously the beginning of the fourth set was important because I managed to get momentum back. I felt like I served well for the most part," says Murray, who will next play France's Adrian Mannarino.
"It was tough, I had to do a lot of defending tonight, a lot of running in humid conditions.
"He's unpredictable and he can play all of the shots, he serves well, it was a very tricky match and I just fought hard, mixed it up and managed to get through."
"Nick Kyrgios played a pretty good match - he would have won that match against the majority of players. But Andy Murray handled that well. I was very impressed with the way he finished that match and he was hitting it as clean as a whistle at the end."
*Murray 7-5 6-3 4-6 6-1 Kyrgios
Murray beats Kyrgios
Kyrgios still capable of those showstopping winners, but those sorts of shots rarely win you matches, it takes a little more than that - patience, clever game management, consistency.
Murray with a match point. Kyrgios forehand long. And Murray progresses to the second round.
"We're back to the Nick Kyrgios from the first and second sets. He can't help himself going for the extravagant shots."
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David Law
BBC Radio 5 live commentator
"This is a great set of tennis from Andy Murray but this a bit of a capitulation from Nick Kyrgios."
Murray 7-5 6-3 4-6 5-1 Kyrgios*
Murray has responded to losing the third set like you'd expect the third best player in the world to. When Kyrgios went for a break after the third set he would've thought he had a chance, but within two games of the fourth he was as good as out of it.
"Great preparation, really good," Kyrgios shouts in Lleyton Hewitt's direction. Murray marches on, an ace to move to within a game of victory.
Post update
Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"There were a few jeers and boos there."
Post update
David Law
BBC Radio 5 live commentator
"Kyrgios has just thrown it away with a massive second serve that doesn't even make the service box."
*Murray 7-5 6-3 4-6 4-1 Kyrgios
Murray breaks
Kerpow! Murray upping the ante, a venomous backhand winner down the line brings up two break points. Kyrgios lasers an ace down the 'T' to save one but surrenders with a whimper with a double fault and some members of the crowd hiss.
Post update
Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"Kyrgios has got to be thinking, 'If I don't play perfect tennis from here on in, then I'm done.'"
"It's just too cavalier for that moment. Kyrgios is not going to get many more chances - he doesn't want to waste them."
Murray 7-5 6-3 4-6 3-1 Kyrgios*
The former champ miscues a forehand and it's the first time we've seen the Scot allow his frustrations to boil over. For most of the match it's been Kyrgios enjoying monologues on the baseline. Kyrgios, though, messes up, he has Murray on the backfoot but casually floats a forehand over the line. Hold to 30 for the Scot.
"Andy Murray knows how important this part of the match is. He's got his man where he wants him and he doesn't want to let up. He knows how dangerous Kyrgios can be."
*Murray 7-5 6-3 4-6 2-1 Kyrgios
Another drop shot from Kyrgios and it's the wrong option, into the net it goes and Murray levels at 30-30. Kyrgios with a cracker of a serve followed by a peachy forehand down the line and the Aussie has won his first game.
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Post update
David Law
BBC Radio 5 live commentator
"Kyrgios has won the match on the highlight reel but he's not winning on the court."
Murray 7-5 6-3 4-6 2-0 Kyrgios*
A beautifully disguised drop shot from Kyrgios bamboozles Murray, the Aussie looking like he was preparing for a bulldozer of a backhand not a feather-shot drop shot. 15-15. No dramas to talk of, Murray serving out to consolidate his break. Kyrgios winning just the one point so far in this set.
"Andy used the break that Kyrgios took to go to the toilet to think about the job he needs to do - and he got straight back to work. He's now in the driving seat again in the match."
*Murray 7-5 6-3 4-6 1-0 Kyrgios
Murray breaks
Kyrgios caring little about those on the other side of the world who need some shut eye but can't take their eyes away from this match. Lleyton Hewitt nodding in his protege's direction as he gets ready to start the fourth set.
Murray ups the ante, kissing the paint with a forehand down the line - three break points. A sloppy drop shot from Kyrgios which bounces into the tramlines and Murray coming off the ropes and counter-punching.
Getty ImagesCopyright: Getty Images
Post update
Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"Is Kyrgios evolving and growing in front of our eyes? He won that set in a boring fashion. Maybe he will put one plus one together. Maybe this is his time..."
"The first two sets seemed like soap opera - all these antics. But that all disappeared in the third set and it worked to his advantage. Kyrgios is playing great at the moment."
Murray 7-5 6-3 4-6 Kyrgios*
Kyrgios wins third set
Murray is broken to love. A more composed and careful Kyrgios wins the third set and could there be a few more twists in this match?
Murray 7-5 6-3 4-5 Kyrgios
Kyrgios swinging freely, hitting the line, and two huge forehands sets him up nicely at 0-30. Murray helpless, simply watching the ball fizz by. Double fault Murray. Three set points Kyrgios.
Post update
Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"Is Kyrgios the sort of player who can light it up and reel it off two or three sets against the number three in the world? The answer is yes, so Andy needs to keep his seatbelt fastened."
"You can see the frustration from Andy but Kyrgios is playing smart - he's not giving him a chance to make inroads."
*Murray 7-5 6-3 4-5 Kyrgios
The servers in control in this set and Kyrgios opting for the solid rather than the spectacular and getting his rewards. A hold to love and Murray must hold to stay in this set.
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Murray 7-5 6-3 4-4 Kyrgios*
A trouble-free hold for Murray. Kyrgios nicks one point as Murray's forehand drifts long - but he sees of Kyrgios for a hold to 15.
"Andy really wanted to make his move there and he wasn't allowed to by Kyrgios, who has calmed down and is playing more of a percentage game. This has got the potential to be a really competitive set. Andy is going to have to fight here."
*Murray 7-5 6-3 3-4 Kyrgios
Will Murray pounce? He doesn't get a chance. Sharp-shooting from Kyrgios opens a 40-15 lead...and eventually he closes out, a forehand winner for a hold to 30.
"It doesn't look like Kyrgios is going to be Mr Consistent, but he's got the potential to have some huge results. I can see him bringing it together and I really think he can win Grand Slams in his career."
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Murray 7-5 6-3 3-3 Kyrgios*
The Murray serve hitting the target more often than not, an ace eases him to 30-15, but a double fault - his first of the match - allows Kyrgios back in the game at 40-30. Crosscourt backhand winner Murray. Game over.
"The guy he has in his corner right now, Lleyton Hewitt - if Kygrios can take advantage of that and make it last..."
Post update
Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"I can't tell if Kyrgios coachable or not. Is anyone out there prepared to funnel this guy into a great player?"
*Murray 7-5 6-3 2-3 Kyrgios
Interesting choice of socks by the young players at the US Open. Bright pink for Borna Coric on Monday, while Kyrgios has opted for luminous yellow. We're back in the late 80s and dancing in the Hacienda. Anyway, on the court, Kyrgios has held to love.
"It looks like Andy's going to get through this match - and it's going to stand him in good stead for the tournament."
Murray 7-5 6-3 2-2 Kyrgios*
Nearly two hours have been played and Murray, for the majority of the match, has performed solidly. No dramas, no major hiccups. Two aces from Murray as he holds to love and levels.
"That will be a cause of real frustration for Kygrios. He played really well to break - and then it's given back in a flash."
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*Murray 7-5 6-3 1-2 Kyrgios
Murray breaks back
And just when there was some light for Kyrgios to walk into... the skies darken again.. Murray with a fabulous passing shot to bring up three break back points, and the Scot simply needs the one. Ruthless from Murray.
"Nick Kygrios played a really solid game - I can't remember a Hollywood shot. He's in the box seat now."
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Murray 7-5 6-3 0-2 Kyrgios*
Kyrgios breaks
Kyrgios getting his rewards on the Murray second serve, three clean winners on the Scot's slower boomers. Fourth break point Kyrgios - Murray forehand into the net! The Aussie finally takes his opportunity.
Murray 7-5 6-3 0-1 Kyrgios
Second break point Kyrgios and it's a second break point saved, the Aussie's backhand directing the ball into the tape. Kyrgios' response? To throw his racquet onto the ground. No damage done, though.
Kyrgios stepping in on the serve, a winning backhand for a third break point - Kyrigos' 12th break point of the match - but the Aussie gambles on the forehand - and it sails long. Deuce. Advantage. Deuce.
Murray 7-5 6-3 0-1 Kyrgios*
Rat-a-tat-tat. Quick-hitting, big-hitting. Murray 30-0 up - but he slaps a forehand into the net on the next point. It looks hot and sticky on Ashe, Murray sweating like a man wearing a duffle coat in a sauna.
Kyrgios levels to 30-30, sometimes even a defender of Murray's caliber can't handle Kyrgios' crackerjack shots.
Super rally on the next point... from side to side... tension increases with every shot... and it's Murray who folds, ending a 26-shot rally by netting. Break point Kyrgios - but Murray produces a perfectly-timed ace. Deuce.
"Kyrgios has the hold at the start of the set, and that's very important for him."
*Murray 7-5 6-3 0-1 Kyrgios
Murray squanders break point
Murray leaves the court for what we presume is a toilet break, while Kyrgios sinks further and further into his chair, his neck disappearing into his shoulders, if that's possible.
But eventually the third set gets under way. 30-30 makes it interesting. A Murray lob, which earns him a break point, makes it very interesting indeed. Murray drags a forehand into the tramlines. Deuce.
Murray long with a forehand, then into the net with a backhand. Opportunity gone.
"Andy Murray went about his business exactly as he needed to in that second set. But Kyrgios missing returns - he made it too easy. He doesn't look ready to win a match like this."
Murray 7-5 6-3 Kyrgios*
Murray wins second set
While Kyrgios wastes energy talking to himself, Andy Murray gathers a 40-0 advantage and secures an easy-peasy hold, Kyrgios - who has yet to win a set against the Scot - netting.
"With shots like that one between the legs, is Kyrgios here to win the match or is he here to put on a show?"
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*Murray 7-5 5-3 Kyrgios
Quick-fire serving from Kyrgios and the young Australian holds to 15, which means Murray will serve out for the set.
Murray 7-5 5-2 Kyrgios*
A backhand volley down the line from Murray returns the game to deuce, and once again Kyrgios loses grip of his racquet.
Plenty of chances coming the Aussie's way... but he's only grabbed one of his last eight break points.
Fourth break point Kyrgios. Fourth break point saved. Fantastic defending from the Scot at the net, a fine backhand volley turning the momentum.
Through-the-legs volley from Kyrgios for some reason when he could have opted for a simple forehand and it bounces long. Advantage Murray. The pair go back and forth from deuce to advantage. Kyrgios going for the extravagant when the simple would do - another rash forehand, into the tape, and Murray is nearly two sets up.
Murray 7-5 4-2 Kyrgios
Murray controlling this match, but Kyrgios allowing him to do so. The Aussie has a number of tricks in his bag, but he doesn't quite know how to use his weapons effectively. The 20-year-old constantly talking to himself in between points. He has two break points, but he allows them to slip through his fingers.
Deuce. Super-duper forehand from Kyrgios, as if the weight of a thousand bears were behind it, and it earns him a third break point.
"Andy wants to shut the door here and get to 5-2."
Post update
David Law
BBC Radio 5 live commentator
"Kyrgios has never taken a set off Murray in his career..."
*Murray 7-5 4-2 Kyrgios
Murray breaks
Kyrgios slumped again in his chair during the changeover, the body language of a teenager whose mum has confiscated his bottle of hooch before the big house party.
Two break points Murray. A backhand into the tramlines from Kyrgios and the Aussie, shoulders slumped, shakes his head.
Post update
Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"Kyrgios is acting like he's mother just put him to sleep. It's junior antics."
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David Law
BBC Radio 5 live commentator
"Kyrgios gets his drink, slumps into his chair... and looks utterly fed up. He has turned his towel into a pillow and he's resting his head on it."
Murray 7-5 3-2 Kyrgios*
Murray saves three break points
One break point saved by Murray... On the next point Kyrgios' eyes widen as the court opens up, but he overcooks a forehand down the line and Murray has dragged this game to deuce.
Kyrgios collects a third break point, but the Murray first serve - big and to the wings - gets the Scot out of trouble. Deuce once more.
A ninth ace from Murray, advantage; a faulty Kyrgios return on the next point and what's that sound? The Aussie's chance whistling in the wind.
Post update
Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"Murray has just got to keep Kyrgios on a tether until it's time to strike."
Murray 7-5 2-2 Kyrgios
Two break points Kyrgios
Swashbuckling shots from Kyrgios and the Aussie gets his rewards, skipping 15-30 ahead. Murray nets a simple forehand after Kyrgios takes control after a weak Murray second serve. Two break points Kyrgios...
Post update
David Law
BBC Radio 5 live commentator
"I know Kyrgios has said some things that are out of order, but you just can't not watch him when he's playing tennis."
"He's playing so quickly that he doesn't have time to think about the size of the point."
*Murray 7-5 2-2 Kyrgios
Kyrgios saves two break points
A woman in the crowd is showing her friend something on her smartphone and they giggle heartily. Perhaps they should share the joke with Kyrgios because the Aussie doesn't seem to be enjoying himself on Ashe.
Murray with a break point - Kyrigos saves with a forehand down the line which Murray pushes wide. Deuce. A brilliant rally ensues... from side to side they go until Kyrgios moves forward... Murray with a flicked crosscourt forehand which is called out but actually kissed the tramline. Dreamy.
Break point Murray. A second break point saved with a howitzer serve out wide. Big-hitting at big moments from Kyrgios and we're level.
"If Andy knuckles down and Kygrios stays in this state, the set could get away from him pretty quickly."
Post update
Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"We've all been saying he's a little too loose, but that's just taking it a bit too far..."
Murray 7-5 2-1 Kyrgios*
Another drop shot from Kyrgios but panther-like speed from the Scot at the net. Murray can gobble them up all night long. (It's watching Murray pounce on iffy drop shots which inspired Lionel Richie to write one of his most famous hits... Little known fact that.)
Kyrgios attempts a forehand and he loses control of his racquet, his weapon flying high before dropping onto the court. The Aussie an entertainer is so many ways.
It's a straightforward hold for Murray, who concludes with a delicious drop shot which Kyrgios can't fetch.
"Kyrgios is a performer but it's almost like he wants to play 10-out-of-10 tennis for the whole match - and it's just not possible. I don't know what he wants from his tennis. He looks so despondent and so upset at the moment."
*Murray 7-5 1-1 Kyrgios
Kyrgios looks like a man who would rather be somewhere else, but he still manages a comfortable hold to level with Murray. The missed opportunities of the previous set still playing on his mind.
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Murray 7-5 1-0 Kyrgios*
Nick Kyrgios leaning back in his chair, eyes closed and slumped, like a man enjoying an afternoon siesta after being under the sun's rays for a tad too long. Hot and bothered and a little fed up. The Aussie certainly has his own ways of doing things.
Murray with the speed of a sprinter as he races to the net and beats his opponent with a super crosscourt winner. The Scot mixing it up - an eighth ace of the match - and the 20-year-old Kyrgios can't handle those Murray boomers.
"The way he did that will have put some doubts into Kygrios's mind."
Post update
Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"There was a little bit of rope-a-dope in that set - Andy wanted to see how much Kygrios had - but he stepped it up to nine and a half when he needed too. That's why he's a Grand Slam winner."
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*Murray 7-5 Kyrgios
Murray wins first set
Andy Murray complaining about something to the umpire during the changeover. Kyrgios serving to stay in the set. Again. Will Murray up the aggression? A brilliant lob helps him with the first point but on the next point Kyrgios is alert to the Murray lob, advances to the net and smashes it. 15-15.
The Kyrgios backhand falters, Murray ahead once again. Two set points Murray.
Kyrgios with a boomer to the Murray ribcage and follows up by swaggering to the net and putting away an overhead. Cool. On the next point Murray steps in on the return and produces a bulldozing winner! That's the first set done and dusted.
"It's a tough match for the umpire - it's only the first set and we've already got both players having a go at him."
Post update
Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"Andy in the last couple of changes of ends is really consuming the umpire's time, and part of that is to stop Kyrgios talking to him."
Murray 6-5 Kyrgios*
At 30-30, the pendulum could swing either way. Murray far from his best, if it wasn't for those aces he'd be in trouble. An edge-of-the-seat rally... the pair trade blows from the baseline and Murray goes on the attack, threading an irretrievable forehand down the line for 40-30. The Scot pulls through.
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Post update
Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"It's night time and I feel like I need sunglasses just to look at Kyrgios's socks and shoes."
"Nick Kyrgios's hair is a Mario Balotelli special."
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*Murray 5-5 Kyrgios
A brilliant rally, from side to side they lunge, Murray defending stoutly... but Kyrgios is brave, a feather-soft drop shot and Murray can't get to it. To deuce we go. The Aussie back from the brink, his audacity paying off.
Murray 5-4 Kyrgios
Kyrgios serving to stay in the match and the 20-year-old's audacity is his enemy. He opts for the difficult when the routine would be better and he's 0-30 down. Trouble? Perhaps.
Murray unable to turn the screw as he botches a backhand during a rally and we're level at 30-30. A fine serve - or was it? Apparently not. Murray challenges and Kyrgios' effort was well long. Double fault. Set point Murray!
Post update
Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"That's a really important game for Andy Murray. I don't want to see him in a tie-break with Kyrgios, who is very unpredictable. Andy can't have peaks and valleys - he needs to be steady as a rock."
Murray 5-4 Kyrgios*
Kyrgios nips ahead at 15-30, two unforced errors from Murray giving his opponent a sniff. The Scot eases the tension with an ace, then another - 40-30.
The Aussie dictating from the baseline as they pair slug it out and Murray is caught out of position and fails to negotiate the barrier. Deuce. Kyrgios' forehand goes long. Game point Murray. Kyrgios forehand return drifts wide. Game Murray. Over to you, Mr Kyrgios.
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*Murray 4-4 Kyrgios
Oops. Kyrgios attempts a slam dunk but the Aussie is no Michael Jordan and misses it. He smiles as he watches the replay.
30-30 - an opportunity for Murray? Nope. Kyrgios holds with little fuss - we're level again.
"That's why we love watching Nick Kygrios's tennis. He's got such talent."
Murray 4-3 Kyrgios*
Murray's serve now on song, the Scot arrowing an ace down the T - his fifth of the match - to go 40-0 up.
Bravo! Kyrgios backpedaling... a through-the-legs shot... over the net it goes... Murray with a forehand... more circus tricks from Kyrgios, a flick of the wrist for an unstoppable forehand crosscourt winner. thigh-slappingly good.
But one moment of brilliance does not win a game and Murray wraps up the hold on the next point.
Post update
Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"Kyrgios really plays by the seat of his pants. You just never know what you're going to get out of his game."
*Murray 3-3 Kyrgios
Latecomers still making their way to their seats. If the umpire sees them they will be in trouble. Kyrgios not in any bother on his own serve, racing to a 40-0 lead. Murray to the net, putting away an overhead, to nick a point back for 40-15.
But more brilliance from Kyrgios, pulling Murray towards the tape with a drop shot before beating his opponent with a snappy forehand down the line.
"Nick Kyrgios has really got himself into a little bit of a strop about the crowd."
Murray 3-2 Kyrgios*
Murray's most comfortable service game so far, concluding with an ace, and he walks to his chair a contented man, wiping his sweaty face with a towel in silence, while Kyrgios is complaining about something or other to the umpire.
Murray 2-2 Kyrgios
Piers Newbery
BBC Sport
Quote Message: Roger Federer spoke earlier about the different conditions on Ashe now the large part of a roof has been constructed above it. The Swiss said it had removed wind from the equation and, sitting courtside, it does feel like an indoor match - steamy.
Roger Federer spoke earlier about the different conditions on Ashe now the large part of a roof has been constructed above it. The Swiss said it had removed wind from the equation and, sitting courtside, it does feel like an indoor match - steamy.
Post update
Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"That was a little bit of a soft break from Kyrgios. That drop shot into the next was a pooper scooper. Kyrgios screaming to his box about the stupidity of those shots."
*Murray 2-2 Kyrgios
Murray breaks
The pair battle it out from the baseline... Murray fetching and retrieving... Kyrgios with a clumsy forehand and Murray breaks back. A clench of the fist from the British number one.
*Murray 1-2 Kyrgios
Three break points Murray
Murray the more passive of the two, the slower to come out of the blocks. Kyrgios' weighty groundstrokes causing the Scot some concern. It's too early to talk of shocks and surprises though as Kyrgios let's two points slip and begins a monologue by the service line as he prepares to serve.
An iffy drop shot from the Aussie... three break points Murray...An immediate riposte from the Scot.
A big first serve from Kyrgios. 15-40. Brilliant! A deft volley - 30-40.
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Post update
Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"He's not only hitting the ball hard, but he's hitting it deep."
"Kyrgios has really earned that break - he has settled into this match more quickly. Andy needs to find a way back into this match."
Murray 1-2 Kyrgios*
Kyrgios breaks
At 15-0 a baseline rally ensues and it's Kyrgios who falters, slapping a backhand into the tape. He must be more patient if he is to overcome the Scot. Signs that Kyrgios will try to attack the Scot's second serve as he advances to the tape in an attempt to pounce on one of Murray's slower balls - but he messes up.
At 30-30, a booming Kyrgios forehand into the corner forces Murray to scamper and the Brit's reply fails to get over the barrier. Break point Kyrgios. Interesting.
Murray on the attack... stepping in... but his backhand bounces over the baseline!
"When Andy is looking to be aggressive with his backhand, I really think it's the best backhand in the world. He gets it flying through the court and he's got incredible control."
*Murray 1-1 Kyrgios
The retiring Lleyton Hewitt has been helping the troubled 20-year-old - even inviting his compatriot to his home in the Bahamas to help fine-tune his game before this tournament. Life isn't so bad for the bad boy of tennis after all.
Hewitt court-side watching his fellow Aussie and he'll be pleased with what he's seen so far. Kyrgios eases to 40-0 and he wraps up a hold to 15 with an ace down the 'T'. Crisp, confident hitting from Kyrgios.
BBC SportCopyright: BBC Sport
Murray 1-0 Kyrgios*
A third ace from Murray takes him to within a point of a hold. It hasn't been easy so far, but three aces suggests the Briton is slowly finding his groove.
Kyrgios not overawed by the occasion, but it is Murray who comes out on top of this one. A hold for the Scot. No early surprises to talk of.
Murray 0-0 Kyrgios*
40-40
"Sit down, please," the umpire tells a few tardy fans. "Please be seated," he repeats before issuing another impatient plea. Eventually, we are under way.
Murray, dressed in Jonny Cash black, allows the two opening points slip, but conjures up an ace, then the young Australian balloons a forehand long and we're level. Murray fans at ease. But not for long.
The first "come on" of the match from Kyrgios as Murray slices a backand into the tape to gift his opponent a break point. A second ace of the match comes to the Scot's rescue. To deuce we go.
BBC SportCopyright: BBC Sport
Murray to serve first
Here we go. The warm-up is over. It's business time. Murray to serve first
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Murray v Kyrgios head-to-head
Two minutes of the warm-up remains so it's probably best to tell you that Murray leads the head-to-head, winning all three of their previous matches.
Nick Kyrgios might have generated more column inches than Andy Murray in recent weeks, but it's the Scot who has won the most titles and matches this year.
BBC SportCopyright: BBC Sport
What you might have missed
Roger Federer is through! Simona Halep is through! Lleyton Hewitt is through! Garbine Muguruza is through!
Unlike Monday, there have been no surprise results at Flushing Meadows today. Five-time champion Roger Federer needed just 77 minutes to beat Argentina's Leonardo Mayer.
There's been British success too as Jo Konta and Aljaz Bedene have progressed to the second round.
The important bit: there's live coverage of this match on BBC Radio 5 live, which you can access on this page. There will also be words like this to guide you through the match.
BBC SportCopyright: BBC Sport
'Murray the greatest athlete on Tour'
The players are making their way out onto Ashe, but they must do the obligatory pre-match interview before strolling under the lights.
"I think this is why you play the game, another chance to play on the biggest court in the world, to play against Andy Murray,"Kyrgios tells Sky Sports.
On Murray, Kyrgios adds: "He's the greatest athlete on Tour, his defence is second to none."
Post update
Hello! Welcome to live coverage of Andy Murray's ding-dong with Nick Kyrgios. It's the British number one, a third seed playing better than ever, facing a young Australian whose latest indiscretion involves a fine and suspended ban for comments made about Stan Wawrinka's girlfriend during a recent match in Montreal.
There could be a slip of the tongue, or a slip-up, we just don't know which is why it's so intriguing.
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He's the sharp-tongued bad boy of tennis everyone's talking about. A 20-year-old who has generated more headlines than a veteran. Misunderstood or mixed up? Who knows. But will Nick Kyrgios be today's headline act for his tennis or his tongue?
Live Reporting
Aimee Lewis
All times stated are UK
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Murray directs a few tennis balls into the crowd before leaving the court, which means it's time for us to wrap things up. If you want to read the match report of Murray's match click here. All the latest results are on our, well, results page. Thanks for joining us.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"Andy Murray's focus looks really good. He doesn't look like's he's got much stress, but he's got the 'grrrr' if he needs it. He looks mentally fresh and ready to go. There's not really much pressure on him because he's not the one everyone is talking about to win the tournament."
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Colin Fleming
British doubles player on BBC Radio 5 live
"Nick Kyrgios can hold his head up pretty high after that match. He has shown the potential he has got tonight. Andy Murray is looking in great shape and it's exciting to see how he moves through this tournament."
Day 3 schedule
Wednesday's order of play has been announced and the night matches (from 00:00 BST) will involve Venus Williams and Novak Djokovic.
Arthur Ashe Stadium
Madison Keys (USA) v Tereza Smitkova
Marin Cilic (Cro) v Evgeny Donskoy (Rus)
Serena Williams (USA) v Kiki Bertens (Ned)
Irina Falconi (USA) v Venus Williams (USA)
Novak Djokovic (SRB) V Andreas Haider-Maurer
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David Law
BBC Radio 5 live commentator
"There were flashes of brilliance from Kyrgios - there was the usual Kyrgios show. But Andy Murray coped with all that."
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"Obviously the beginning of the fourth set was important because I managed to get momentum back. I felt like I served well for the most part," says Murray, who will next play France's Adrian Mannarino.
"It was tough, I had to do a lot of defending tonight, a lot of running in humid conditions.
"He's unpredictable and he can play all of the shots, he serves well, it was a very tricky match and I just fought hard, mixed it up and managed to get through."
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Colin Fleming
British doubles player on BBC Radio 5 live
"Nick Kyrgios played a pretty good match - he would have won that match against the majority of players. But Andy Murray handled that well. I was very impressed with the way he finished that match and he was hitting it as clean as a whistle at the end."
*Murray 7-5 6-3 4-6 6-1 Kyrgios
Murray beats Kyrgios
Kyrgios still capable of those showstopping winners, but those sorts of shots rarely win you matches, it takes a little more than that - patience, clever game management, consistency.
Murray with a match point. Kyrgios forehand long. And Murray progresses to the second round.
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Colin Fleming
British doubles player on BBC Radio 5 live
"We're back to the Nick Kyrgios from the first and second sets. He can't help himself going for the extravagant shots."
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David Law
BBC Radio 5 live commentator
"This is a great set of tennis from Andy Murray but this a bit of a capitulation from Nick Kyrgios."
Murray 7-5 6-3 4-6 5-1 Kyrgios*
Murray has responded to losing the third set like you'd expect the third best player in the world to. When Kyrgios went for a break after the third set he would've thought he had a chance, but within two games of the fourth he was as good as out of it.
"Great preparation, really good," Kyrgios shouts in Lleyton Hewitt's direction. Murray marches on, an ace to move to within a game of victory.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"There were a few jeers and boos there."
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David Law
BBC Radio 5 live commentator
"Kyrgios has just thrown it away with a massive second serve that doesn't even make the service box."
*Murray 7-5 6-3 4-6 4-1 Kyrgios
Murray breaks
Kerpow! Murray upping the ante, a venomous backhand winner down the line brings up two break points. Kyrgios lasers an ace down the 'T' to save one but surrenders with a whimper with a double fault and some members of the crowd hiss.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"Kyrgios has got to be thinking, 'If I don't play perfect tennis from here on in, then I'm done.'"
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Colin Fleming
British doubles player on BBC Radio 5 live
"It's just too cavalier for that moment. Kyrgios is not going to get many more chances - he doesn't want to waste them."
Murray 7-5 6-3 4-6 3-1 Kyrgios*
The former champ miscues a forehand and it's the first time we've seen the Scot allow his frustrations to boil over. For most of the match it's been Kyrgios enjoying monologues on the baseline. Kyrgios, though, messes up, he has Murray on the backfoot but casually floats a forehand over the line. Hold to 30 for the Scot.
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Colin Fleming
British doubles player on BBC Radio 5 live
"Andy Murray knows how important this part of the match is. He's got his man where he wants him and he doesn't want to let up. He knows how dangerous Kyrgios can be."
*Murray 7-5 6-3 4-6 2-1 Kyrgios
Another drop shot from Kyrgios and it's the wrong option, into the net it goes and Murray levels at 30-30. Kyrgios with a cracker of a serve followed by a peachy forehand down the line and the Aussie has won his first game.
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David Law
BBC Radio 5 live commentator
"Kyrgios has won the match on the highlight reel but he's not winning on the court."
Murray 7-5 6-3 4-6 2-0 Kyrgios*
A beautifully disguised drop shot from Kyrgios bamboozles Murray, the Aussie looking like he was preparing for a bulldozer of a backhand not a feather-shot drop shot. 15-15. No dramas to talk of, Murray serving out to consolidate his break. Kyrgios winning just the one point so far in this set.
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Get involved #bbctennis
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David Law
BBC Radio 5 live commentator
"Murray did what champions do."
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Colin Fleming
British doubles player on BBC Radio 5 live
"Andy used the break that Kyrgios took to go to the toilet to think about the job he needs to do - and he got straight back to work. He's now in the driving seat again in the match."
*Murray 7-5 6-3 4-6 1-0 Kyrgios
Murray breaks
Kyrgios caring little about those on the other side of the world who need some shut eye but can't take their eyes away from this match. Lleyton Hewitt nodding in his protege's direction as he gets ready to start the fourth set.
Murray ups the ante, kissing the paint with a forehand down the line - three break points. A sloppy drop shot from Kyrgios which bounces into the tramlines and Murray coming off the ropes and counter-punching.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"Is Kyrgios evolving and growing in front of our eyes? He won that set in a boring fashion. Maybe he will put one plus one together. Maybe this is his time..."
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Colin Fleming
British doubles player on BBC Radio 5 live
"The first two sets seemed like soap opera - all these antics. But that all disappeared in the third set and it worked to his advantage. Kyrgios is playing great at the moment."
Murray 7-5 6-3 4-6 Kyrgios*
Kyrgios wins third set
Murray is broken to love. A more composed and careful Kyrgios wins the third set and could there be a few more twists in this match?
Murray 7-5 6-3 4-5 Kyrgios
Kyrgios swinging freely, hitting the line, and two huge forehands sets him up nicely at 0-30. Murray helpless, simply watching the ball fizz by. Double fault Murray. Three set points Kyrgios.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"Is Kyrgios the sort of player who can light it up and reel it off two or three sets against the number three in the world? The answer is yes, so Andy needs to keep his seatbelt fastened."
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Colin Fleming
British doubles player on BBC Radio 5 live
"You can see the frustration from Andy but Kyrgios is playing smart - he's not giving him a chance to make inroads."
*Murray 7-5 6-3 4-5 Kyrgios
The servers in control in this set and Kyrgios opting for the solid rather than the spectacular and getting his rewards. A hold to love and Murray must hold to stay in this set.
Murray 7-5 6-3 4-4 Kyrgios*
A trouble-free hold for Murray. Kyrgios nicks one point as Murray's forehand drifts long - but he sees of Kyrgios for a hold to 15.
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Colin Fleming
British doubles player on BBC Radio 5 live
"Andy really wanted to make his move there and he wasn't allowed to by Kyrgios, who has calmed down and is playing more of a percentage game. This has got the potential to be a really competitive set. Andy is going to have to fight here."
*Murray 7-5 6-3 3-4 Kyrgios
Will Murray pounce? He doesn't get a chance. Sharp-shooting from Kyrgios opens a 40-15 lead...and eventually he closes out, a forehand winner for a hold to 30.
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Colin Fleming
British doubles player on BBC Radio 5 live
"It doesn't look like Kyrgios is going to be Mr Consistent, but he's got the potential to have some huge results. I can see him bringing it together and I really think he can win Grand Slams in his career."
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Murray 7-5 6-3 3-3 Kyrgios*
The Murray serve hitting the target more often than not, an ace eases him to 30-15, but a double fault - his first of the match - allows Kyrgios back in the game at 40-30. Crosscourt backhand winner Murray. Game over.
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Colin Fleming
British doubles player on BBC Radio 5 live
"The guy he has in his corner right now, Lleyton Hewitt - if Kygrios can take advantage of that and make it last..."
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"I can't tell if Kyrgios coachable or not. Is anyone out there prepared to funnel this guy into a great player?"
*Murray 7-5 6-3 2-3 Kyrgios
Interesting choice of socks by the young players at the US Open. Bright pink for Borna Coric on Monday, while Kyrgios has opted for luminous yellow. We're back in the late 80s and dancing in the Hacienda. Anyway, on the court, Kyrgios has held to love.
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Colin Fleming
British doubles player on BBC Radio 5 live
"It looks like Andy's going to get through this match - and it's going to stand him in good stead for the tournament."
Murray 7-5 6-3 2-2 Kyrgios*
Nearly two hours have been played and Murray, for the majority of the match, has performed solidly. No dramas, no major hiccups. Two aces from Murray as he holds to love and levels.
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Russell Fuller
BBC tennis correspondent at Flushing Meadows
"That will be a cause of real frustration for Kygrios. He played really well to break - and then it's given back in a flash."
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*Murray 7-5 6-3 1-2 Kyrgios
Murray breaks back
And just when there was some light for Kyrgios to walk into... the skies darken again.. Murray with a fabulous passing shot to bring up three break back points, and the Scot simply needs the one. Ruthless from Murray.
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Colin Fleming
British doubles player on BBC Radio 5 live
"Nick Kygrios played a really solid game - I can't remember a Hollywood shot. He's in the box seat now."
Get involved #bbctennis
Murray 7-5 6-3 0-2 Kyrgios*
Kyrgios breaks
Kyrgios getting his rewards on the Murray second serve, three clean winners on the Scot's slower boomers. Fourth break point Kyrgios - Murray forehand into the net! The Aussie finally takes his opportunity.
Murray 7-5 6-3 0-1 Kyrgios
Second break point Kyrgios and it's a second break point saved, the Aussie's backhand directing the ball into the tape. Kyrgios' response? To throw his racquet onto the ground. No damage done, though.
Kyrgios stepping in on the serve, a winning backhand for a third break point - Kyrigos' 12th break point of the match - but the Aussie gambles on the forehand - and it sails long. Deuce. Advantage. Deuce.
Murray 7-5 6-3 0-1 Kyrgios*
Rat-a-tat-tat. Quick-hitting, big-hitting. Murray 30-0 up - but he slaps a forehand into the net on the next point. It looks hot and sticky on Ashe, Murray sweating like a man wearing a duffle coat in a sauna.
Kyrgios levels to 30-30, sometimes even a defender of Murray's caliber can't handle Kyrgios' crackerjack shots.
Super rally on the next point... from side to side... tension increases with every shot... and it's Murray who folds, ending a 26-shot rally by netting. Break point Kyrgios - but Murray produces a perfectly-timed ace. Deuce.
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Russell Fuller
BBC tennis correspondent at Flushing Meadows
"Kyrgios has the hold at the start of the set, and that's very important for him."
*Murray 7-5 6-3 0-1 Kyrgios
Murray squanders break point
Murray leaves the court for what we presume is a toilet break, while Kyrgios sinks further and further into his chair, his neck disappearing into his shoulders, if that's possible.
But eventually the third set gets under way. 30-30 makes it interesting. A Murray lob, which earns him a break point, makes it very interesting indeed. Murray drags a forehand into the tramlines. Deuce.
Murray long with a forehand, then into the net with a backhand. Opportunity gone.
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Colin Fleming
British doubles player on BBC Radio 5 live
"Andy Murray went about his business exactly as he needed to in that second set. But Kyrgios missing returns - he made it too easy. He doesn't look ready to win a match like this."
Murray 7-5 6-3 Kyrgios*
Murray wins second set
While Kyrgios wastes energy talking to himself, Andy Murray gathers a 40-0 advantage and secures an easy-peasy hold, Kyrgios - who has yet to win a set against the Scot - netting.
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Colin Fleming
British doubles player on BBC Radio 5 live
"With shots like that one between the legs, is Kyrgios here to win the match or is he here to put on a show?"
Get involved #bbctennis
*Murray 7-5 5-3 Kyrgios
Quick-fire serving from Kyrgios and the young Australian holds to 15, which means Murray will serve out for the set.
Murray 7-5 5-2 Kyrgios*
A backhand volley down the line from Murray returns the game to deuce, and once again Kyrgios loses grip of his racquet.
Plenty of chances coming the Aussie's way... but he's only grabbed one of his last eight break points.
Fourth break point Kyrgios. Fourth break point saved. Fantastic defending from the Scot at the net, a fine backhand volley turning the momentum.
Through-the-legs volley from Kyrgios for some reason when he could have opted for a simple forehand and it bounces long. Advantage Murray. The pair go back and forth from deuce to advantage. Kyrgios going for the extravagant when the simple would do - another rash forehand, into the tape, and Murray is nearly two sets up.
Murray 7-5 4-2 Kyrgios
Murray controlling this match, but Kyrgios allowing him to do so. The Aussie has a number of tricks in his bag, but he doesn't quite know how to use his weapons effectively. The 20-year-old constantly talking to himself in between points. He has two break points, but he allows them to slip through his fingers.
Deuce. Super-duper forehand from Kyrgios, as if the weight of a thousand bears were behind it, and it earns him a third break point.
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Colin Fleming
British doubles player on BBC Radio 5 live
"Andy wants to shut the door here and get to 5-2."
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David Law
BBC Radio 5 live commentator
"Kyrgios has never taken a set off Murray in his career..."
*Murray 7-5 4-2 Kyrgios
Murray breaks
Kyrgios slumped again in his chair during the changeover, the body language of a teenager whose mum has confiscated his bottle of hooch before the big house party.
Two break points Murray. A backhand into the tramlines from Kyrgios and the Aussie, shoulders slumped, shakes his head.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"Kyrgios is acting like he's mother just put him to sleep. It's junior antics."
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David Law
BBC Radio 5 live commentator
"Kyrgios gets his drink, slumps into his chair... and looks utterly fed up. He has turned his towel into a pillow and he's resting his head on it."
Murray 7-5 3-2 Kyrgios*
Murray saves three break points
One break point saved by Murray... On the next point Kyrgios' eyes widen as the court opens up, but he overcooks a forehand down the line and Murray has dragged this game to deuce.
Kyrgios collects a third break point, but the Murray first serve - big and to the wings - gets the Scot out of trouble. Deuce once more.
A ninth ace from Murray, advantage; a faulty Kyrgios return on the next point and what's that sound? The Aussie's chance whistling in the wind.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"Murray has just got to keep Kyrgios on a tether until it's time to strike."
Murray 7-5 2-2 Kyrgios
Two break points Kyrgios
Swashbuckling shots from Kyrgios and the Aussie gets his rewards, skipping 15-30 ahead. Murray nets a simple forehand after Kyrgios takes control after a weak Murray second serve. Two break points Kyrgios...
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David Law
BBC Radio 5 live commentator
"I know Kyrgios has said some things that are out of order, but you just can't not watch him when he's playing tennis."
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Colin Fleming
British doubles player on BBC Radio 5 live
"He's playing so quickly that he doesn't have time to think about the size of the point."
*Murray 7-5 2-2 Kyrgios
Kyrgios saves two break points
A woman in the crowd is showing her friend something on her smartphone and they giggle heartily. Perhaps they should share the joke with Kyrgios because the Aussie doesn't seem to be enjoying himself on Ashe.
Murray with a break point - Kyrigos saves with a forehand down the line which Murray pushes wide. Deuce. A brilliant rally ensues... from side to side they go until Kyrgios moves forward... Murray with a flicked crosscourt forehand which is called out but actually kissed the tramline. Dreamy.
Break point Murray. A second break point saved with a howitzer serve out wide. Big-hitting at big moments from Kyrgios and we're level.
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Colin Fleming
British doubles player on BBC Radio 5 live
"If Andy knuckles down and Kygrios stays in this state, the set could get away from him pretty quickly."
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"We've all been saying he's a little too loose, but that's just taking it a bit too far..."
Murray 7-5 2-1 Kyrgios*
Another drop shot from Kyrgios but panther-like speed from the Scot at the net. Murray can gobble them up all night long. (It's watching Murray pounce on iffy drop shots which inspired Lionel Richie to write one of his most famous hits... Little known fact that.)
Kyrgios attempts a forehand and he loses control of his racquet, his weapon flying high before dropping onto the court. The Aussie an entertainer is so many ways.
It's a straightforward hold for Murray, who concludes with a delicious drop shot which Kyrgios can't fetch.
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Colin Fleming
British doubles player on BBC Radio 5 live
"Kyrgios is a performer but it's almost like he wants to play 10-out-of-10 tennis for the whole match - and it's just not possible. I don't know what he wants from his tennis. He looks so despondent and so upset at the moment."
*Murray 7-5 1-1 Kyrgios
Kyrgios looks like a man who would rather be somewhere else, but he still manages a comfortable hold to level with Murray. The missed opportunities of the previous set still playing on his mind.
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Murray 7-5 1-0 Kyrgios*
Nick Kyrgios leaning back in his chair, eyes closed and slumped, like a man enjoying an afternoon siesta after being under the sun's rays for a tad too long. Hot and bothered and a little fed up. The Aussie certainly has his own ways of doing things.
Murray with the speed of a sprinter as he races to the net and beats his opponent with a super crosscourt winner. The Scot mixing it up - an eighth ace of the match - and the 20-year-old Kyrgios can't handle those Murray boomers.
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Colin Fleming
British doubles player on BBC Radio 5 live
"The way he did that will have put some doubts into Kygrios's mind."
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"There was a little bit of rope-a-dope in that set - Andy wanted to see how much Kygrios had - but he stepped it up to nine and a half when he needed too. That's why he's a Grand Slam winner."
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*Murray 7-5 Kyrgios
Murray wins first set
Andy Murray complaining about something to the umpire during the changeover. Kyrgios serving to stay in the set. Again. Will Murray up the aggression? A brilliant lob helps him with the first point but on the next point Kyrgios is alert to the Murray lob, advances to the net and smashes it. 15-15.
The Kyrgios backhand falters, Murray ahead once again. Two set points Murray.
Kyrgios with a boomer to the Murray ribcage and follows up by swaggering to the net and putting away an overhead. Cool. On the next point Murray steps in on the return and produces a bulldozing winner! That's the first set done and dusted.
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Colin Fleming
British doubles player on BBC Radio 5 live
"It's a tough match for the umpire - it's only the first set and we've already got both players having a go at him."
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"Andy in the last couple of changes of ends is really consuming the umpire's time, and part of that is to stop Kyrgios talking to him."
Murray 6-5 Kyrgios*
At 30-30, the pendulum could swing either way. Murray far from his best, if it wasn't for those aces he'd be in trouble. An edge-of-the-seat rally... the pair trade blows from the baseline and Murray goes on the attack, threading an irretrievable forehand down the line for 40-30. The Scot pulls through.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"It's night time and I feel like I need sunglasses just to look at Kyrgios's socks and shoes."
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Colin Fleming
British doubles player on BBC Radio 5 live
"Nick Kyrgios's hair is a Mario Balotelli special."
Get involved #bbctennis
*Murray 5-5 Kyrgios
A brilliant rally, from side to side they lunge, Murray defending stoutly... but Kyrgios is brave, a feather-soft drop shot and Murray can't get to it. To deuce we go. The Aussie back from the brink, his audacity paying off.
Murray 5-4 Kyrgios
Kyrgios serving to stay in the match and the 20-year-old's audacity is his enemy. He opts for the difficult when the routine would be better and he's 0-30 down. Trouble? Perhaps.
Murray unable to turn the screw as he botches a backhand during a rally and we're level at 30-30. A fine serve - or was it? Apparently not. Murray challenges and Kyrgios' effort was well long. Double fault. Set point Murray!
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"That's a really important game for Andy Murray. I don't want to see him in a tie-break with Kyrgios, who is very unpredictable. Andy can't have peaks and valleys - he needs to be steady as a rock."
Murray 5-4 Kyrgios*
Kyrgios nips ahead at 15-30, two unforced errors from Murray giving his opponent a sniff. The Scot eases the tension with an ace, then another - 40-30.
The Aussie dictating from the baseline as they pair slug it out and Murray is caught out of position and fails to negotiate the barrier. Deuce. Kyrgios' forehand goes long. Game point Murray. Kyrgios forehand return drifts wide. Game Murray. Over to you, Mr Kyrgios.
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*Murray 4-4 Kyrgios
Oops. Kyrgios attempts a slam dunk but the Aussie is no Michael Jordan and misses it. He smiles as he watches the replay.
30-30 - an opportunity for Murray? Nope. Kyrgios holds with little fuss - we're level again.
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Colin Fleming
British doubles player on BBC Radio 5 live
"That's why we love watching Nick Kygrios's tennis. He's got such talent."
Murray 4-3 Kyrgios*
Murray's serve now on song, the Scot arrowing an ace down the T - his fifth of the match - to go 40-0 up.
Bravo! Kyrgios backpedaling... a through-the-legs shot... over the net it goes... Murray with a forehand... more circus tricks from Kyrgios, a flick of the wrist for an unstoppable forehand crosscourt winner. thigh-slappingly good.
But one moment of brilliance does not win a game and Murray wraps up the hold on the next point.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"Kyrgios really plays by the seat of his pants. You just never know what you're going to get out of his game."
*Murray 3-3 Kyrgios
Latecomers still making their way to their seats. If the umpire sees them they will be in trouble. Kyrgios not in any bother on his own serve, racing to a 40-0 lead. Murray to the net, putting away an overhead, to nick a point back for 40-15.
But more brilliance from Kyrgios, pulling Murray towards the tape with a drop shot before beating his opponent with a snappy forehand down the line.
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Colin Fleming
British doubles player on BBC Radio 5 live
"People want to see the bad behaviour - they want to see that side of Nick Kyrgios."
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Russell Fuller
BBC tennis correspondent at Flushing Meadows
"Nick Kyrgios has really got himself into a little bit of a strop about the crowd."
Murray 3-2 Kyrgios*
Murray's most comfortable service game so far, concluding with an ace, and he walks to his chair a contented man, wiping his sweaty face with a towel in silence, while Kyrgios is complaining about something or other to the umpire.
Murray 2-2 Kyrgios
Piers Newbery
BBC Sport
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"That was a little bit of a soft break from Kyrgios. That drop shot into the next was a pooper scooper. Kyrgios screaming to his box about the stupidity of those shots."
*Murray 2-2 Kyrgios
Murray breaks
The pair battle it out from the baseline... Murray fetching and retrieving... Kyrgios with a clumsy forehand and Murray breaks back. A clench of the fist from the British number one.
*Murray 1-2 Kyrgios
Three break points Murray
Murray the more passive of the two, the slower to come out of the blocks. Kyrgios' weighty groundstrokes causing the Scot some concern. It's too early to talk of shocks and surprises though as Kyrgios let's two points slip and begins a monologue by the service line as he prepares to serve.
An iffy drop shot from the Aussie... three break points Murray...An immediate riposte from the Scot.
A big first serve from Kyrgios. 15-40. Brilliant! A deft volley - 30-40.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live
"He's not only hitting the ball hard, but he's hitting it deep."
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Colin Fleming
British doubles player on BBC Radio 5 live
"Kyrgios has really earned that break - he has settled into this match more quickly. Andy needs to find a way back into this match."
Murray 1-2 Kyrgios*
Kyrgios breaks
At 15-0 a baseline rally ensues and it's Kyrgios who falters, slapping a backhand into the tape. He must be more patient if he is to overcome the Scot. Signs that Kyrgios will try to attack the Scot's second serve as he advances to the tape in an attempt to pounce on one of Murray's slower balls - but he messes up.
At 30-30, a booming Kyrgios forehand into the corner forces Murray to scamper and the Brit's reply fails to get over the barrier. Break point Kyrgios. Interesting.
Murray on the attack... stepping in... but his backhand bounces over the baseline!
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Colin Fleming
British doubles player on BBC Radio 5 live
"When Andy is looking to be aggressive with his backhand, I really think it's the best backhand in the world. He gets it flying through the court and he's got incredible control."
*Murray 1-1 Kyrgios
The retiring Lleyton Hewitt has been helping the troubled 20-year-old - even inviting his compatriot to his home in the Bahamas to help fine-tune his game before this tournament. Life isn't so bad for the bad boy of tennis after all.
Hewitt court-side watching his fellow Aussie and he'll be pleased with what he's seen so far. Kyrgios eases to 40-0 and he wraps up a hold to 15 with an ace down the 'T'. Crisp, confident hitting from Kyrgios.
Murray 1-0 Kyrgios*
A third ace from Murray takes him to within a point of a hold. It hasn't been easy so far, but three aces suggests the Briton is slowly finding his groove.
Kyrgios not overawed by the occasion, but it is Murray who comes out on top of this one. A hold for the Scot. No early surprises to talk of.
Murray 0-0 Kyrgios*
40-40
"Sit down, please," the umpire tells a few tardy fans. "Please be seated," he repeats before issuing another impatient plea. Eventually, we are under way.
Murray, dressed in Jonny Cash black, allows the two opening points slip, but conjures up an ace, then the young Australian balloons a forehand long and we're level. Murray fans at ease. But not for long.
The first "come on" of the match from Kyrgios as Murray slices a backand into the tape to gift his opponent a break point. A second ace of the match comes to the Scot's rescue. To deuce we go.
Murray to serve first
Here we go. The warm-up is over. It's business time. Murray to serve first
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Murray v Kyrgios head-to-head
Two minutes of the warm-up remains so it's probably best to tell you that Murray leads the head-to-head, winning all three of their previous matches.
Nick Kyrgios might have generated more column inches than Andy Murray in recent weeks, but it's the Scot who has won the most titles and matches this year.
What you might have missed
Roger Federer is through! Simona Halep is through! Lleyton Hewitt is through! Garbine Muguruza is through!
Unlike Monday, there have been no surprise results at Flushing Meadows today. Five-time champion Roger Federer needed just 77 minutes to beat Argentina's Leonardo Mayer.
There's been British success too as Jo Konta and Aljaz Bedene have progressed to the second round.
For all the latest results visit our results page or read a round-up of the Brits and the best of the rest.
BBC Coverage
The important bit: there's live coverage of this match on BBC Radio 5 live, which you can access on this page. There will also be words like this to guide you through the match.
'Murray the greatest athlete on Tour'
The players are making their way out onto Ashe, but they must do the obligatory pre-match interview before strolling under the lights.
"I think this is why you play the game, another chance to play on the biggest court in the world, to play against Andy Murray,"Kyrgios tells Sky Sports.
On Murray, Kyrgios adds: "He's the greatest athlete on Tour, his defence is second to none."
Post update
Hello! Welcome to live coverage of Andy Murray's ding-dong with Nick Kyrgios. It's the British number one, a third seed playing better than ever, facing a young Australian whose latest indiscretion involves a fine and suspended ban for comments made about Stan Wawrinka's girlfriend during a recent match in Montreal.
There could be a slip of the tongue, or a slip-up, we just don't know which is why it's so intriguing.
Post update
He's the sharp-tongued bad boy of tennis everyone's talking about. A 20-year-old who has generated more headlines than a veteran. Misunderstood or mixed up? Who knows. But will Nick Kyrgios be today's headline act for his tennis or his tongue?