Wide on the backhand by Novak Djokovic. Deuce.

After holding serve again, Novak Djokovic starts the next return game with an excellent backhand winner down the line.

There's another dream of a backhand, this time cross court, to earn a first set point...

Stan Wawrinka has left the court for a medical timeout at the end of the third set.

Anna Kalinskaya, who received treatment on her back at the break, is looking in a bit of discomfort. Her shoulders are down each time she goes through her pre-serve routine.

However, she's showing grit to stick around in baseline exchanges with Iga Swiatek, not allowing the second seed to get a step inside the court as she fights back from 15-30 to complete a confidence-boosting hold.

Good news from the outside courts, where play has resumed as the heat rules have been relaxed.

Pat Cash
Former Wimbledon champion on BBC Radio 5 Sports Extra

That was a huge set. Stan Wawrinka has got to go to five [sets] now and for him to somehow sneak back into that set and grab it would have been huge for him.

A big ask now for Stan.

Image source, Reuters

Taylor Fritz had been utterly dominant on serve in the third set, conceding three holds to love before finally conceding a point in the eighth game.

However, he makes a meal of closing out the set, spurning three set points at 40-0 and saving a break point before finally converting at the fifth attempt with a forehand winner.

He's looking a bit out of sorts but he leads 2-1. Can Stan the Man force a fifth set?

He is human.

Novak Djokovic sends a forehand long for his first unforced error of the match in game number six.

But he gets to deuce on Botic van de Zandschulp's serve - a chance for a double break...

Not this time.

Image source, Getty Images

Iga Swiatek has taken the first set in just 24 minutes, converting her second set point.

The Pole not only converted two of her three break points but only dropped four points on serve.

Anna Kalinskaya is receiving treatment on her back at the break.

Iga Swiatek had, in her own words, "many ups and downs" in the first round and looked a bit flaky on serve at times in the second round but she's PUMPED today.

She's manipulating Anna Kalinskaya all around the court and the 31st seed isn't being helped by her wayward forehand. She plants one into the tramlines to concede a second break of the set.

Andy Lapthorne
Six-time US Open quad champion on BBC Radio 5 Sports Extra

This is the real Novak Djokovic, this is the relaxed Djokovic that we've seen for so many years and he's loving it already.

He's getting the crowd going and it was a huge rally there, the perfect start now with the early break of serve.

Novak Djokovic backs up the break with a comfortable service hold to move 4-1 in front in the opening set.

No unforced errors by the Serb in the first five games.

Stan Wawrinka holds to love. John Cain Arena roars.

Taylor Fritz will serve for a 2-1 lead.

Image source, Getty Images

Great defensive work from Novak Djokovic keeps him in a point that he eventually wins when his opponent nets a volley.

Botic van de Zandschulp goes wide on the forehand side at 15-30 and now Djokovic has two break points.

A smashed winner by the Dutchman saves the first, but Djokovic outlasts Van de Zandschulp in a 26-shot rally to secure the first break.

No wonder he's asking the crowd for more noise - that was outstanding from the 24-time Grand Slam champion.

Anna Kalinskaya gets on the board, racing through her second service game with a hold to love.

Iga Swiatek produces a similarly dominant hold to 15. Kalinskaya tried to attack the second seed at 40-15 but got caught in two minds with her volley and put it into the net.

*denotes next server

I jinxed that, didn't I?

Taylor Fritz draws first blood in the third set, converting the second of his two break points to lead 4-3.

He's produced three aces and is yet to drop a point on serve in the third set, so Stan Wawrinka will have his work cut out to break back.

Andy Lapthorne
Six-time US Open quad champion on BBC Radio 5 Sports Extra

It works both ways with the roof being on the stadium, you can take big swings at the ball indoors and there's no wind or conditions to move the ball around.

Both ends are going to be confident in taking big swings at the ball.

Listen to live commentary on BBC Sounds and via the link at the top of this page.

The third set is going with serve on John Cain Arena.

Only one of the opening six service games hasn't been held to love, with Stan Wawrinka dropping two points in the third game.

Taylor Fritz is cutting a frustrated figure on the baseline. Wawrinka, who keeps attacking the net, has the full support of the crowd. "Let's go, Stan, let's go!" drowns out every break in play.

Novak Djokovic finds himself 0-30 down on serve but sends down two aces, the second of them on a second serve, to bring it back to 30-30.

But it's Botic van de Zandschulp who will have the first break point of the match... he goes wide with a forehand so misses that first opportunity.

Djokovic sees it home from deuce and we remain on serve.

Iga Swiatek shows some early aggression, greeting Anna Kalinskaya's first serve of the match with a booming backhand winner.

The 31st seed wins the next three points before a double fault and a netted forehand invite pressure on her serve.

In the second deuce, Kalinskaya nets a routine forehand to concede advantage. She then engages in a cross-court backhand battle with Swiatek and although succeeds in dragging the Pole off court, another loose stroke costs her the game.

Swiatek holds to 30 to consolidate the break.