A slow Nishioka serve is punished by Murray for 30-30 in the eight game of the second set.

But Nishioka takes the next two points, a powerful forehand at the net and then Murray sends one long and the Japanese world number 49 is one game away from the second set.

Murray opts to mix it up with a serve-volley and Nishioka nets off his backhand. Nishioka then goes long and that's three games on the bounce for Murray.

The fighting spirit from Murray has never gone. He still needs to break Nishioka's serve and has two chances to do so.

Image source, Reuters

Sixteenth seed Elise Mertens has just won her match against Laura Siegemund 6-2 6-2 on court five, so Britain's Johanna Konta and Heather Watson should be out soon.

It's the third time the Fed Cup team-mates will face each other in a top-level match and Konta said earlier this week there won't be any extra emotion involved in playing her friend.

"Regardless of who I am drawn against, it will be a tough match," she said.

"Obviously, I knew there would be added interest from home and it makes it more exciting for people at home, which is nice and gets people more into our sport.

"I'm looking forward to it, it will be a tough match for me and she is a very good player who has won a title this year."

Image source, Getty Images

David Law
BBC Radio 5 Live Sports Extra tennis commentator

Andy really took it to Nishioka there. If Nishioka is able to continue playing this level, Murray is going to have to take it to him. The other side is that Nishioka's form could evaporate.

An aggressive Murray gets one of the two breaks back. After a few mistakes from his opponent Murray takes a forehand out of the sky and we've got a game back on.

Murray claws a break back but still trails 4-2 in the second.

Three unforced errors from Nishioka. Two break points for Murray.

A cross-court backhand volley at the net brings a smile to the Murray face. He then unleashes the anger that being a set and two breaks down brings as he bullets a swiping forehand away.

Murray has taken his first game of the second set. He had not lost all games in a set since the Miami Open final in April 2015 against Novak Djokovic and he avoids that today. Nishioka leads 4-1 but at least the Brit has a game on the board in this set and something to build on.

Three shots in a row down the line for Murray. The first two are reached, the third - a low, sliding volley coming into the net - is unanswered. That gives Murray another chance for his first game of the second set.

But a netted smash means it is deuce once more.

The first serve, as it has often been today, is no good, too long from Murray and a tasty backhand shot down the line from Nishioka as Murray moves into the net and that's another deuce.

Coach Jamie Delgado is looking a worried man. Nishioka takes us to deuce in the fifth game, before a rare error from him sends it into the net to give Murray a much-needed game point.

An incredible two-handed backhand from Nishioka finds the corner. Even a 100% fit Murray may have struggled with that one. 0-15

Naomi Broady
British player on BBC Radio 5 Live Sports Extra

Will Andy keep trying to win this set now or will he let it go and try to conserve his energy? Pump himself up for a big comeback starting in the third set?

Image source, EPA

Yoshihito Nishioka is aiming to get into the second round of the US Open for the third time in his career. He managed that in 2015 after disposing of Kyle Edmund in one of the qualifying rounds.

Nishioka also got into the last 64 in 2019 but lost to Feliciano Lopez, the man Murray partnered at Queen's last summer as the pair won the men's doubles title.

Nishioka extends his lead to 4-0, with a forceful volley.

Naomi Broady
British player on BBC Radio 5 Live Sports Extra

Murray started off playing a bit too defensively. He's started to be a bit more aggressive but with that has come more mistakes.

This is not how Andy Murray would've dreamed this one going last night. He's struggling on his serve with four double faults already in this set, Nishioka, a set up, now has a double-break advantage in the second.

This is already looking a long way back for the former world number one.

Murray, after his fourth double fault in two service games, moves into the net but can only punch a volley into the net. Break point Nishioka.

Murray came up with two double faults in the opening game of this set and has just produced another one. 0-15

Murray nets a backhand return and Nishioka holds to love to sprint into a 2-0 lead in this second set.

Naomi Broady
British player on BBC Radio 5 Live Sports Extra

We can only expect so much of Murray when he's played hardly any matches even with the Battle of the Brits.

He'll still be feeling rusty and won't be at his best level for a while I can't imagine.

He's being quite calm for when Andy's not playing his best tennis so it might be expected.

Nishioka is looking the fresher of the two players, darting around the court at high pace and high energy. Murray, talking to himself, says "flat as a pancake", presumably describing his own energy levels.

The Brit then sends a forehand long and the Japanese man now has a set and a break advantage.