Image source, EPA

What a turnaround. Murray holds with consummate ease and now holds the edge in this third set.

A sweetly-sliced backhand from Murray stays too low for Tsonga, who falls 0-30 down. A backhand pass gives Murray three break points, and he needs only one as Tsonga pushes a backhand wide. Murray, staring at a double break just moments ago, is right back in this third set.

Worrying medical time out for seventh seed Eugenie Bouchard in her game against Ekaterina Makarova.

She's having her blood pressure taken in the sweltering New York heat, is taking salt tablets and there's tears in her eyes as bags of ice are run down her arms to try and bring down her temperature.

Bouchard lost the first set 7-6 to her Russian opponent and is 3-2 down, with serve, in the second.

Thankfully, it looks like she'll continue.

Tsonga has the proverbial bit between his teeth now and is really going for his shots on the Murray serve. He passes Murray at the net then greets a second serve with a disdainful return winner to get himself a break point.

Murray staves off the danger, but after working his socks off to earn a game point, he serves a double fault. Two more break points are saved, the second with an ace before Murray can finally stumble over the line.

Now then, another big test for Murray. Little chance of a comeback just yet though as Tsonga opens up a 40-0 lead with some huge serves then wins the game when Murray's return flies wide.

Image source, Getty Images

Both players left the court at the end of the second set for a comfort break, but both have returned so, to paraphrase Liverpool captain Steven Gerrard, we go again.

Tsonga stepping in from the baseline on the Murray second serve and the Frenchman punishes the Briton, eking a 15-30 advantage. Impressive scampering from Murray, though, scooting to the net to level at 30-30.

But Murray coughs up a double fault to present Tsonga with a break point and Murray embarks on one of his angry monologues. Tsonga ruthless from the baseline on a Murray second serve and takes his chance!

Hashim Albahbahani:, external Tsonga is so frustrating to watch! How in the world did he lose that set?

Chris Rhydderch: , externalAndy Murray now 2 sets up but it's traditional that he'll now lose the 3rd!!

Jeff Tarango
Former professional tennis player on BBC Radio 5 live sports extra

"Andy is playing really good tennis, but he's so unpredictable physically. He's grunting and groaning, holding his back. It's tough to read what he's really feeling out there. Because of the humidity and the conditions, the players are so moody. So many ups and downs emotionally."

Tsonga reacts to the danger of falling 15-30 behind with a 128mph ace, then puts away a smash after watching Murray somehow hang on deep into a point that was never his to win. Murray catches Tsonga unawares with a looped return into the forehand corner and we're at deuce.

Murray seems to be in pain here as he holds his ribs, but there's little effect on his game as two more fine returns earn him a break point. Make that three fine returns of serve! Tsonga can't handle the pace on Murray's forehand and the British number one is one set away from the quarter-finals.

David Law
BBC Radio 5 live sports extra commentator

"I think Jo-Wilfried Tsonga deserves a tie-break and I think this set deserves a tie-break."

A cleverly-worked point from Murray earns the approval of coach Amelie Mauresmo, who sports a light-weight pink T-shirt at she watches her charge. Even Tsonga applauds Murray when he flies across the court to get his racquet to what looked a sure-fire winner and places a backhand into the court.

Tom: , externalMurray playing a blinding few games, needed to fight fire with fire and stepped up.

Chris Braithwaite:, external Murray just stepped it up a gear. Wow. These boys hit the ball so hard.

Image source, AP

Tsonga has removed his pesky cap, and is now exposing his noggin to the sweltering sun. The Frenchman's serve seems to have recovered some of its zip as he holds to 15, sealing the game with an emphatic overhead. At 5-5 in the second set, we're into a key phase of the match.

Piers Newbery
BBC Sport at Flushing Meadows

"Come on, Jo Jo!" There's plenty of support around Ashe for the Tsonga comeback, with the stands continuing to fill up at each changeover, but the blistering run of points that saw Murray break back and then hold serve had the New Yorkers on their feet and fist pumping like the days of Connors.

Murray is pumped up now, belting through his next service game without even looking like losing a point. Tsonga, in contrast, looks woozy and stunned, his final effort a disastrous drop shot that loops into the net.

David Law
BBC Radio 5 live sports extra commentator

"Tsonga can't quite believe this. I haven't seen Murray play this aggressively in a long time."

Jeff Tarango
Former professional tennis player on BBC Radio 5 live sports extra

"Every forehand Murray hit was 20% harder in that point. Now it's Tsonga taking a little extra time, redoing his shoelaces."

This is bubbling up into quite a match, with both men scrapping out every point on a humid New York afternoon. Murray forces the game to deuce and saves a game point by chasing down an under-hit drop shot and slamming it across the court. A horribly wayward Tsonga forehand presents Murray with a chance to break back, but Tsonga saves it with his sixth ace of the match. A bulldozer of a return gives Murray another break point, and this time he take it with a fizzing forehand crosscourt pass.

Tsonga has made 24 unforced errors to Murray's nine, and yet we could soon be level at one set all. Tsonga makes Murray work hard to hold serve, but the Scot puts it away with a sublime forehand drop shot, which spins off the court and out of Tsonga's reach.

John McEnerney:, external Both of these guys suffer from lapses in concentration, Andy less over the last few years but it still happens! Eye on the prize!

pauline smith: , externalCome on Andy! Going to US Open this week and I would like to see you playing!