Whatever happens in this match, Kei Nishikori might have found himself a new gameplan for the future. He's normally a baseliner but is currently 14/15 at the net.

It's not often you'll have stats like that and lose. The man he is playing the is looking sensational however. Another game is in the bag for Novak.

David Law
BBC Radio 5 live sports extra commentator at Flushing Meadows

Nishikori is hitting the ball pretty much as hard as he possibly can but it's just not getting any success. So he is giving it more! The only real success he is having is when he goes into the net.

Novak Djokovic is like that dream bad that just comes back again and again for Kei Nishikori. The relentless former world number one breaks through eventually.

Nishikori won't have played much better than this and he's down a set and a break.

Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra

Nishikori is playing great at the net!

Kei Nishikori's box are on his feet! The final break point is saved with more rapid footwork and a good volley.

Deuce.

How quick are these two?! Nishikori puts his head down and sprints like a whippet to pick up a drop shot.

Now he bangs away a backhand.

It's still 30-40...

Backhand into the net. Nishikori considers smashes his racquet into two pieces but reconsiders.

Three break points Djokovic.

Danger for Kei Nishikori. He's thrown everything at Djokovic but is now under pressure on his own serve again.

0-30.

Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra

I feel privileged that we are here watching this level of tennis.

Will Novak Djokovic change his game to see off this new aggressive gameplan from Kei Nishikori? No signs of it yet. He's happy to stick to his baseline game. It works. He levels up.

If you're just making your way in from a night out, Rafael Nadal had to retire from his semi-final with Juan Martin del Potro due to a knee injury.

I can't believe we've only played three games in this set. The first set lasted 37 minutes. The first three games of the second have almost gone on as long. That's all credit to Kei Nishikori. He's upped his game. The 21st seed is charging into the net now. He wins three points in this latest game at the front.

David Law
BBC Radio 5 live sports extra commentator at Flushing Meadows

Nishikori has played his worst tennis of the set on his two break points!

Ah. Nishikori just can't find that brilliant play on the break point. He nets again and swishes an arm in frustration.

Djokovic holds. Nishikori's purple and black shirt is soaked with sweat. He's going to have a change.

Nishikori is bounding around now. He's at the top of his game. Djokovic is distracted. Here's another break point.

David Law
BBC Radio 5 live sports extra commentator at Flushing Meadows

Djokovic is getting angry here. He has just flat-batted a forehand away in frustration. I'm glad it didn't hit anybody!

Djokovic is ticking. He grins and nods sarcastically after some noise from the crowd when he misses his first serve on break point.

Nishikori nets after.

Deuce.

Double fault from Djokovic - his second of the game. The Serb drops his racquet and holds his arms out wide while glaring at his box.

Break point Nishikori! It's his first of the match.

Edward Ditchfield: With Roger’s resurgence apparently waning, Rafa breaking down again, and Murray simply out of it, are we seeing the beginning of another stretch of sheer Djokovic dominance?

Djokovic is now showing the signs of the effort he put into that last game. He's collar is spread wide and a big necklace is dangling on the outside of his white shirt.

Nishikori has got himself into a Djokovic service game.

Deuce.