The question now is - can Mannarino hold his nerve? And his energy levels in this sapping New York heat? Murray doesn't look too worried yet, skipping around the net after a rapid hold of serve at the start of the third set.

 BBC tennis commentator David Law:   "It is very rare for Andy Murray to go out of Grand Slam tournaments very early - he is just so consistent."   

Wow. The barnstorming second set from Andy Murray did not materialise. Adrian Mannarino holds out to love, forcing Murray wide before volleying home into an unguarded court for the second set. The Frenchman, as you would expect, looks rather smug as he gulps down some water at the changeover.

Can you believe this? Andy Murray can't. He looks shocked after some Mannarino magic puts the Frenchman within a hold of the second set...

Mannarino relinquishes control with a pair of unforced errors for 40-30 and then the inexplicable happens. Back-to-back double faults from the Frenchman. Uh oh. That hands a break point to the Briton, but a gutsy ace from Mannarino hauls the game back into his favour and he scrambles a hold.

Image source, Reuters

Neither of these fellas look like giving up their serves in a hurry - that's what I was going to say as Mannarino eased into a 40-0 lead. The Frenchman continues to vary his service game, giving Murray plenty of food for thought. But then he hits the self-destruct button as Murray battles back...

Slam! That's the sound of the door being closed rather firmly on Adrian Mannarino. Andy Murray produces an impeccable service game to hit back with a hold to love of his own. Sealed with ace too. That's Murray's 13th ace of the match - unlucky for Mannarino.

Anyone expect this match to be as tight as this? Nope, me neither. I thought I was going to scarper from the office in time for the last tram. That ain't happening.

Another confident hold from the Frenchman...Murray going long with a baseline forehand to concede the game to love.

What a hold! Murray hangs on by his fingernails in this game - but serves his way out of trouble. Once, twice, three times, Mannarino tees up break points. And three times Murray salvages the situation with blistering serves. 

In between that drama Murray takes a whack on the shoulder from a feisty Mannarino forehand. Murray turns his back - rather like I used to do when stood in the wall when defending a free-kick at junior football - but can't dodge out of the way.

Comfortable hold for Mannarino as he races into a 40-0 advantage. Or so it appears. A double fault from the Frenchman - the first of the match - gives a glimmer of hope to Murray, who also takes the next point after a stray forehand from Mannarino. But the world number 35 calms himself to hold.

Choppy waters for Andy Murray. But he navigates them with the skill of Christopher Columbus to hold off Mannarino and clinch the hold with a forehand winner.

Meanwhile, a stone's throw away from Ashe on Court 17, there's more bad news for the British contingent. Aljaz Bedene has been pegged back by American Donald Young, who takes the second set to level at 6-3 4-6.

"Aaarrrgh!" cries Andy Murray, who looks up to the heavens above New York as the second game of the second set closes. And that anguish means Murray hasn't broken Mannarino's serve at the first time of asking. He did have a sniff though, at 0-30, before allowing the Frenchman to sneak back in and whip the break out of his grasp.

Image source, Reuters

Whatever mental processes Andy Murray was going through during the changeover at the end of the first set have done the trick. As have the few gulps of icy water which he has guzzled, I'd imagine. Perfect serving game from the Briton - just the start he needed.

A first set point for Mannarino forces Murray on the attack. The Briton charges forward to guide in a forehand volley winner which helps tee up a fourth break point for the third seed. But another cheeky drop shot from the Frenchman has Muzza scrambling - and even the fleet-footed Scot can't rescue that one. A rogue backhand from Murray hands another set point to his opponent, who has the Briton dashing back and forth across the blue surface. And a routine smash at the net, belted straight down into the court, leaves Mannarino celebrating taking the first set.

Oh Andy! Murray has three break points to take this match into a breaker - and blows them all.

Mannarino goes from the ridiculous to the sublime, smashing into the net from the middle of the court for 0-15, then pulling out an inch-perfect drop-shot to begin the comeback at 15-40. That's the spark he needs to take the game into deuce...

Image source, Getty Images

Well, well, well. I didn't see this one coming. Mannarino has the chance to serve for the opening set after shocking Murray with an aggressive backhand game.   Murray stops in his tracks and stares at his box. A steely glare from Jonas Bjorkman greets him. Murray returns to his seat, chuntering something - probably unrepeatable - to himself at the changeover.

Nope, if Andy Murray is going to win this first set then it is going to take him at least another two games. The Briton yelps and screeches across the baseline as Mannarino digs deep to pin Murray back. And when a Scottish-sounding cry of frustration fills the Ashe air then you know it isn't good news for Murray. A stretching forehand catches the net flush on game point for Mannarino. On we go...

The time it takes me to see what is happening across the office when a round of applause breaks out - someone might have been trapped in the lift or something equally exciting (probably not) - is about the same number of seconds that Andy Murray takes to wrap up his hold. Four straight points - Mannarino had the temerity to nick the first point - are finished with a pair of aces. Murray is a break away from taking the first set...