Singles second round begins on day four of US Open
Britain's Cameron Norrie battles for four hours to beat Francisco Comesana
British number one Jack Draper withdraws from tournament with arm injury
Emma Raducanu drops just three games in dominant victory against qualifier Janice Tjen
Novak Djokovic comes back from a set down to beat qualifier Zachary Svajda
Elena Rybakina, Jakub Mensik and Jessica Pegula all in action
Listen to BBC Radio 5 Sports Extra coverage at top of page (UK only)
Djokovic 6-7 (5-7) 6-3 6-3 6-1 Svajda
Image source, Getty ImagesAs the clock reaches two and a half hours, Novak Djokovic reaches match point.
The Serbian hits a forehand long but then approaches the net and almost slam-dunks a volley to earn a place in the third round.
Norrie 1-2 Comesana*
Cameron Norrie challenges, arguing that there is a double-bounce before Francisco Comesana returns the ball but the replay shows he is incorrect.
There is a delay but it results in him being 0-30 down.
An unforced error follows to give his opponent three break points and despite saving the first, another error allows the Argentine to break.
*Djokovic 6-7 (5-7) 6-3 6-3 5-1 Svajda
It's a completely different match now. Novak Djokovic is totally in control and sends a forehand down the line to seize another break.
Image source, Getty Images*Norrie 1-1 Comesana
Ken Skupski
Former British player on BBC Radio 5 Sports Extra and BBC Sounds
Cam's playing well at the moment. He's got a bit of a Argentinian background with the people that he trains with, so maybe they have an idea of comments on his game. He's been on the tour a little bit now, and it's an opportunity for him to advance. I think he should win this match, but he still has to bring the level.
*Norrie 1-1 Comesana
Francisco Comesana begins his first service game with a double-fault but Cameron Norrie hits in to the net on the next two points.
The Argentine serves out the game with an ace and we are level early on.
Norrie 1-0 Comesana*
A solid start for Cameron Norrie as he recovers from 15-30 to hold his serve.
The Brit elects to pour water all over his hands at the change of ends.
Djokovic 6-7 (5-7) 6-3 6-3 4-1Svajda*
Another love service hold for Novak Djokovic and his team are probably already preparing the ice bath.
It's been a bit of a toil at times for the 24-time Grand Slam champion this afternoon but it looks like he is finally on the home straight.
*Djokovic 6-7 (5-7) 6-3 6-3 3-1 Svajda
Zachary Svajda stops the rot and holds serve but it's a long way back for the American qualifier.
Novak Djokovic is looking much more dialled in now.
Image source, Getty ImagesJack Draper is currently seventh in the ranking list which determines the eight players who will compete in the end-of-year ATP Tour finals.
That event is scheduled to take place in mid-November.
Draper was also defending a huge number of points in New York from his run to last year's semi-finals, so his world ranking is likely to take a hit over the next couple of weeks too.
That won't be of huge concern right now, though - more important will surely be getting back to peak condition.
*Norrie 0-0 Comesana
Cameron Norrie will get us under way on court five.
The winner of this one will face either Novak Djokovic or Zachary Svajda in the next round.
*Djokovic 6-7 (5-7) 6-3 6-3 3-0 Svajda
That's six games in a row for seventh seed Novak Djokovic, who races through his service game to turn the screw on Svajda, who looks to toiling now.
Image source, Getty Images*Djokovic 6-7 (5-7) 6-3 6-3 2-0 Svajda
Novak Djokovic breaks for the fourth time in a row, and surely there is no coming back for Zachary Svajda.
The American qualifer manages to save three break points but a forehand error hands the game to the 24-time Grand Slam champion.
Andrea Petkovic
Former world number nine on BBC Radio 5 Sports Extra and BBC Sounds
I have to say that I'm not entirely surprised that Jack Draper has withdrawn.
I called his mixed doubles semi-final with Jessica Pegula and towards the end of that match he started running around his forehands and just playing backhands. He was trying to avoid those forehands at all costs.
I watched his first-round match and he was significantly lower in his first-serve speeds. The doctor did say he would need eight weeks out, so he did significantly push the envelope here.
Adrenaline can do things to your body, you might feel fine for weeks and after a four-set match it can feel aggravated. Bone injuries are difficult to handle, they can always come back if you come back too early. You have to be disciplined and rest bone injuries completely.
Norrie v Comesana
Image source, Getty ImagesCameron Norrie's recent renaissance at the Grand Slams has continued in New York.
Norrie reached the fourth round at the French Open and then the quarter-finals at Wimbledon earlier this summer.
He followed that up by beating American Sebastian Korda in round one of the US Open - Korda retired injured with Norrie leading by two sets to love.
Former Wimbledon semi-finalist Norrie could potentially face Novak Djokovic in round three if he makes it past Francisco Comesana of Argentina today.
Russell Fuller
Tennis correspondent on BBC Radio 5 Sports Extra and BBC Sounds
Jack Draper possibly aggravated his injury in his first-round match yesterday. Who knows how he felt waking up this morning. It might not have been too bad during the match yesterday, there were no signs of any grimacing or pain.
One thing is for certain though, he must be feeling it a lot worse today. It isn't easy playing a five-set match with an injury like that, especially after being sidelined for a number of weeks. I guess his gamble has backfired in many ways.
We certainly hope he hasn't done more damage, perhaps it's just a case of spending a little bit longer away from the game.
Image source, Getty ImagesNorrie v Comesana
Cameron Norrie's second-round opponent is Argentina's Francisco Comesana.
He is ranked 54th in the world, 19 places below Norrie, and made round three at last year's US Open before losing to eventual finalist Taylor Fritz.
Djokovic 6-7 (5-7) 6-3 6-3 1-0 Svajda*
Djokovic has the advantage of serving first in this fourth set - he secures the game with a backhand winner to put the pressure immediately on Zachary Svadja, who has lost his last three service games.
Russell Fuller
Tennis correspondent on BBC Radio 5 Sports Extra and BBC Sounds
Bad news for Jack Draper. His withdrawal is down to the discomfort in his arm, which he says is too much and therefore he is withdrawing with immediate effect. He will not even try to play his second-round match tomorrow.
He had a scan after Wimbledon, having felt some discomfort in his left arm, and found out it was bruising on the bone between his elbow and his shoulder. He told us it was healed coming into the US Open but did say there was still a bit of discomfort.
It's a big disappointment in the short term, given he was a semi-finalist last year, but there must be some doubt now around whether he's going to be able to play consistently for the rest of this season.
After his first-round victory over Federico Gomez, Jack Draper said he was almost grateful to have been taken to four sets, having not played any singles matches since Wimbledon early in July.
"I needed tennis in my legs. I needed to play a three-hour match," Draper said. "I was almost a bit happy when I lost the third because my level wasn't amazing. Then I felt like towards the end of the fourth I started to get better and better."
He added: "I wasn't too sure if I was going to make it here. I'm not putting too much expectation on myself. I'm so happy to be able to compete."
Unfortunately for the Briton, his tournament is over after just one match.
Djokovic 6-7 (5-7) 6-3 6-3 0-0 Svajda*
Image source, Getty ImagesThings are looking a bit ominous for Zachary Svajda, who drops serve for the third time in a row.
In just over two hours, Djokovic is two sets to one up and seemingly at last on his way to the third round.
