Heather Watson is still managing to hold on to her serve but she’s not making any in-roads into Johanna Konta’s game.

Konta has only lost two points on serve in her first three games. It seems like it’s only a matter of time before the British number one gets a break.

Paul Christie: I know Murray says it is nice just to be back but for a player that's achieved so much in his career if this is the only tennis his body can produce he's better off retiring. Looks a shadow of the player he once was.

David Law
BBC Radio 5 Live Sports Extra tennis commentator

This is one of the worst performances I've ever seen from Andy Murray at a Grand Slam.

He's got a metal hip and he may not be able to do this any more, but looking at this having covered so many of his matches I've never seen anything like this before.

Perhaps he's not feeling very well. I expected to see a fight tooth and nail. His opponent is good and I thought he could cause problems but I expected it to be hyper-competitive and Murray would win, but it's not even close.

Another routine game for Yoshihito Nishioka. If things are going to change in this match they need to do so soon.

But that could be a much-needed boost to the mind as Murray sweeps through his service game.

However, unless he can find a way of dismantling Nishioka's serve, Murray's Grand Slam return is going to fall at the first hurdle.

David Law
BBC Radio 5 Live Sports Extra tennis commentator

It's weird, there's no defiance in Murray - where's the rottweiler that won't let you have it?

He looks a bit resigned and I've not often seen that. It's not a pleasant sight for anyone who has cared for Murray's career over the years.

This is one of the worst performances I've seen by Andy Murray at a Grand Slam tournament.

Let's not forget, this has been a super-human effort from Murray to get himself back to competing at this level after a number of injury-hit years, including a couple of hip surgeries since his last Grand Slam appearance 20 months ago.

Today though it is very much not going his way, as he's struggled on his first serve and made far too many unforced errors. Nishioka takes the game to love.

Konta definitely has the upper hand, but it’s still on serve on court five.

A bullet of a backhand down the line brought up break point for the ninth seed, but an ace down the middle helped Watson on her way to another hold.

Things were much more simple on Konta's serve, as she held to love.

Another double fault, that brings Murray's total up to six, and this one is the most costly as it means Nishioka has an early break, just as he did in the previous set.

Two sets down and a break down. This is a mountain to climb now for the three-time Grand Slam champion.

A forehand into the net is Andy Murray's 33rd unforced error and it also brings about a break-point chance for Nishioka right at the start of the third set. 30-40

Naomi Broady
British player on BBC Radio 5 Live Sports Extra

The momentum was changing there. Although Andy lost that set I think he is coming into the third with the momentum.

Remember we've got live radio commentary available by pressing the play button at the top of this page.

A miss-hit forehand from Murray goes well too long and Nishioka takes the set at the second opportunity.

Two sets gone, the Japanese player has won them both.

There's much less drama over on court five, where both Watson and Konta have claimed straightforward holds to kick things off after some solid serving on both sides of the net.

A backhand volley dashing into the net is a thing of beauty from Murray. That's one break point saved. One remains on the table.

Set point Nishioka.

Nishioka takes the opening two points of what could be the last game of the second set. Two more and he has a 2-0 lead.

The roof is open on the Arthur Ashe Stadium and the early-afternoon sun is sometimes making things tricky for the players. Murray's double fault is the only point he concedes in that game as a weak return from Nishioka means it is four games in five for Murray.

Nishioka is now serving for the set though.

The players hide under umbrellas getting out of the sun and behind both players are screens with dozens of faces on, all cheering and celebrating spotting themselves on the television.

If only they could be here in person. But at least we've got a US Open on and that didn't look likely for a long time.

Naomi Broady
British player on BBC Radio 5 Live Sports Extra

I think this is more positive tennis, even though he lost this game. He is playing much more aggressive tennis now, there is so much more pace on the ball.

Johanna Konta and Heather Watson return to their benches after the warm-up. Konta is very much the favourite for this one and has won all three of their meetings so far.

The British number one reached the quarter-final at Flushing Meadows last year and is coming into the US Open on the back of a run to the Western and Southern Open semi-finals last week.

Watson won a WTA title in Acapulco earlier this year and was unbeaten in the singles at last month's Battle of the Brits exhibition event, but has never made it past the first round in New York.