Stephanie Siu: This is Stephanie following the feed from Watford. I'm calling Murray in 4 sets. Let's do this!

Nicola!: Alarms set for 7am.... So if you could make quick work of this Murray that would be great...

dm: As much as I want to stay up, work at 7.30am, could be a 5 set ding doing battle this one. 

Dimitrov might not need to do anything in this game. Two aces and a double fault have him playing no part in the first three points. First shout of support for Murray from the crowd.Some scampering and a pass take the Scot ahead.

Quick switcheroo of ends, baseline battle recommenced. Dimitrov winning a backhand duel, Murray almost standing on top of the net when he gets a look at a second serve. Not that it does him any good, Dimitrov holds to 15. Keep an eye on that, though. 

Image source, Getty Images

Slugfest on. Haymakers thrown from the back of the court, each man barely making his opponent move. An early test of strength. After snoozing to 15-40, Murray holds in the first game.

Image source, Getty Images

And another boomer which the Bulgarian can't keep in. Back level.

An unreturnable. One saved.

Murray, at the far end, arcs his back and springs into the serve. Dimitrov is already looking to come into the net and twice Murray's forehand lets him down. 15-30, then a backhand pass from Dimitrov. Two break points... 

A yawn from Ivan Lendl. He's bored already. Players back to their chairs, Murray bashing his strings like a man playing the tambourine. He'll serve first.

Floodlights beam down, Murray looks around for some balls and then starts to belt serves into an empty court. Spectators file in, carrying brown bags from Bloomingdales, drinking coffee from Central Perk and wearing T-shirts that say "I heart New York".

Some of the above may not be true.

Image source, Getty Images

BBC Radio 5 live sports extra

If you're in the area, you can listen to commentary from those lovely people at 5 live sports extra. Use the audio icon at the top of the page and snuggle under the duvet.

Jeff Tarango
Former professional tennis player

It looks like Dimitrov's trying to be super-positive guy and, to me, some of it isn't genuine. 

Jiten Chandarana: Last year Andy was battling against Anderson on Armstrong. Now he faces another dangerous opponent, this time on Ashe.

Knock-up time, so the opportunity for me to remind you how to get involved. Very straightforward - tweet using the hashtag #bbctennis., external Are you staying up late for this one? Let me know where you are following from.

Dance music greets the pair as they step on to the blue surface, a burnt orange sky above them and the rest of the Big Apple. Murray all in black, just donning a cap. Dimitrov matches him, but brightens things up with luminous shorts. 

Image source, Getty Images

Image source, Getty Images

The players have been spoken to by the media on the way to the court, more bags than a packhorse on their backs. It's like being asked to stop and chat when you're trying to carry the Saturday big shop to you car.

Andy Murray on Eurosport: "I started the tournament well. I didn't play so well in the last match and I need to pick it up from here.

"I want to dictate the points. He can play all the shots, so I have to try to stop him from playing those shots."

So, very much getting to the business end of Murray's quest for a second US Open crown. Win here and he will be a Kei Nishikori away from the last four.

Where once Dimitrov was 'Baby Fed' (the only time I'll be mentioning that), it's now a 'Baby Steps' return to form. 

He's back up to 24 in the world and reached the semis in Cincinnati last month, losing to eventual winner (and Murray conqueror) Marin Cilic.

Despite that, Murray holds the edge in the head-to-head, six wins to three, including the last time they met at a Slam - that eventful Aussie Open of 2015.

He will start as favourite against a man who claims to have "fallen back in love" with tennis after his world ranking fell as low as 40 earlier this year.