Jonathan Jurejko
BBC Sport at Flushing Meadows

That's more like it from Murray.

He's looks a little more locked in now and drawing errors from his opponent is giving him more assurance.

Ah... although he shows at the end of the game he's still far from happy.

First he roars his displeasure at his box after missing a return and then hammers away a loose ball when Nava clinches the hold.

Murray expresses his frustration. There was an opportunity to go two breaks of serve up, but Nava gets his hold.

If Murray can continue to hold his serve, they'll have a set each.

Nava gets to 30-0 fairly comfortably, but struggles in a couple of longer rallies to make it 30-30.

A backhand into the net and that's deuce.

So far, so good in this second set.

Nava's backhand creaks again and Murray stays a break up as he holds serve.

Emilio Nava sends three backhands into the net to make it 40-0, before Andy Murray whacks one so far wide it goes around the side of the net. 40-15.

Naomi Broady
British player on BBC Radio 5 Live

I feel like Murray has upped his intensity. Initially it looked like he was absorbing the pace, but now it looks like he is accelerating through every point.

Just a bit of luck finally for Andy Murray. He's worked hard enough for it.

Murray had only won one of nine break points but he takes that statistic to two in 10.

He clings onto the rally for dear life and will have to clasp on to that break even harder if he is going to stay in this match.

Murray gets a look at 30-0 up on Nava's serve, but the American hits a 128mph serve for 15-30.

But Nava finds the net next and that's two break points for Murray.

Jonathan Jurejko
BBC Sport at Flushing Meadows

Holds to love have been rarer than finding a good cup of English breakfast tea in New York.

Murray earns only his second of the match - and third between the pair overall - and can now perhaps start setting about Nava's serve.

If you're just joining us, former world number one Andy Murray is a set down against world number 203 Emilio Nava.

The 20-year-old snatched a break to close out the first set. It's a bit of an epic - they've already been playing for an hour and 45 minutes.

Just what he needed.

Jonathan Jurejko
BBC Sport at Flushing Meadows

Murray looks very subdued.

The Scot shakes his head as he saunters over to the cool-box behind the umpire's chair.

He grabs some icy fluids which may help to sharpen his mind as well as hydrate his body.

Problems to solve for the 2012 champion.

It is wild to think Emilio Nava is ranked 203rd in the world.

His coach is taking full advantage of the fact that on-court coaching is allowed here, dropping in bits of advice frequently.

It doesn't do anything to help the 20-year-old read Murray's serve on the first point and he sends his backhand into the net for 15-0.

Emilio Nava screams in delight as another ace finally gets him his hold.

Nava is not being as accurate as he was towards the end of the first set, but his serve is saving him in this one.

Naomi Broady
British player on BBC Radio 5 Live

Another big clap of the racquet coming from Nava - we are seeing that consistently throughout this match.

The only question for me is - can Nava sustain this?

Nava gets to 30-30 with an ace, but hits a forehand way wide to give Murray a chance.

Another solid serve slams the door shut, though.

Here we go...

Emilio Nava loops a ball long and Andy Murray has a sniff at 30-0 up on the American's serve.

Things could go either way when Murray goes 0-15 down on his serve.

Thankfully for British tennis fans, they go Murray's way. After a stutter at 40-30, Murray hits a stellar backhand on the line to get his hold.

Naomi Broady
British player on BBC Radio 5 Live

Nava had the biggest grin on his face for the entirety of the first set.

He is absolutely loving being out there.