US Open day five - listen to BBC Radio 5 Live commentary (UK only)
Britain's Harriet Dart knocked out, before Francesca Jones plays later
Title contender Iga Swiatek beats Nadia Podoroska 6-3 6-2
Naomi Osaka fights back to beat Katerina Siniakova 6-2 5-7 6-1
Top seed Alexander Zverev and 2023 winner Coco Gauff feature in night session
Swiatek 6-3 6-2 Podoroska
Iga Swiatek saves one of the shots of the match until near the end as she steps around the ball to crash a forehand winner across court.
She brings up match point with yet another unplayable forehand, before sealing her place in the third round as she forces Nadia Podoroska into an error.
That was an impressive performance from the six-time Grand Slam champion.
Auger-Aliassime 7-6 (7-5) 0-0 Khachanov
Mark Woodforde
17-time Grand Slam doubles champion on BBC Radio 5 Sports Extra 2
With Karen Khachanov, you don't want to give him the same ball all the time.
If I was in Felix Auger-Aliassime's corner I would be advocating trying that backhand slice.
Auger-Aliassime 7-6 (7-5) 0-0 Khachanov
This is a battle between two US Open semi-finalists and it has been a tough start for Felix Auger-Aliassime as he is taken to a tie-break by Karen Khachanov after giving up a break advantage.
However, the third seed digs deep to come out on top in the tie-break 7-5 and takes the first set.
Osaka 6-2 1-0 Siniakova*
Not for the first time this week, the chair umpire has to remind the crowd to keep quiet - or at least be quieter - during the points.
Despite that interruption, Naomi Osaka continues where she left off in the first set - but only after Katerina Siniakova recovers to deuce from 40-15.
Osaka double-faulted on her second game point, but resets to get on the board in set two.
*Swiatek 6-3 5-2 Podoroska
Katie Smith
Presenter on BBC Radio 5 Sports Extra 2
Iga Swiatek is looking to close this out as quickly as she can...
Image source, Getty Images*Swiatek 6-3 5-2 Podoroska
Mark Woodforde
17-time Grand Slam doubles champion on BBC Radio 5 Sports Extra 2
This scoreboard is heavily in favour of Iga Swiatek.
*Swiatek 6-3 5-2 Podoroska
Nadia Podoroska is put under pressure at 30-30 but she holds her nerve well to secure the hold as Iga Swiatek goes long with a backhand.
Podoroska must now fight to stay in the match.
*Osaka 6-2 0-0 Siniakova
Katerina Siniakova can't force Naomi Osaka to serve out the set, conceding a first set point at the end of an error-strewn game.
As far as Osaka is concerned, that was a very satisfying first set and she looks to be well on her way to a place in the third round.
Swiatek 6-3 5-1 Podoroska*
Iga Swiatek is being well supported by pockets of the crowd at Flushing Meadows today.
They will be a touch concerned as Nadia Podoroska's superb backhand winner across court takes the game to deuce, but the Argentine can't capitalise as Swiatek holds with a couple of strong first serves.
Swiatek is one game away from the third round.
Osaka 5-2 Siniakova*
Katerina Siniakova denies Naomi Osaka on another game point, but Osaka sets up a fourth with an ace and is relieved to see Katerina Siniakova narrowly miss the line.
So far, so good for Osaka. She's a game away from the first set.
*Osaka 4-2 Siniakova
Katerina Siniakova reads a second serve and pops away a forehand winner to level at 15-15.
Naomi Osaka fires in an ace out wide to move to game points, but another excellent return from Siniakova brings her to 40-30.
Double fault! This is a real chance for the Czech now...
*Swiatek 6-3 4-1 Podoroska
Image source, Getty ImagesNadia Podoroska is under a bit of pressure before she steps into the court and arrows a backhand winner down the line.
She takes confidence from that to get to game point, but is taken to deuce as Iga Swiatek finds the gap with a forehand winner across court.
Swiatek ups her game to earn break point, before sealing it as Podoroska can't keep her forehand in play.
It's a long way back for Podoroska from here.
*Osaka 4-2 Siniakova
A much-needed straightforward game for Katerina Siniakova stops the run of games against her.
The Czech even throws in an ace, which will feel very good after her early struggles on her first serve.
She manages that on the more challenging side of the court too, in the direct sunlight.
Swiatek 6-3 3-1 Podoroska*
Nadia Podoroska can't lay a glove on Iga Swiatek's serve as the Polish eighth seed holds to love.
Osaka 4-1 Siniakova*
Image source, Getty ImagesKaterina Siniakova gestures to suggest she is losing sight of the ball as it travels between the sunny and shaded halves of the court.
The divide between light and shade is almost perfectly aligned with the net on Arthur Ashe Stadium as we hit midday in New York.
The sun is also bothering Naomi Osaka as she tries to serve.
Siniakova appears to be the more unsettled, however. The Czech is smiling and shaking her head as she misses a return to hand over another comfortable game to Osaka.
*Swiatek 6-3 2-1 Podoroska
Nadia Podoroska serves a double fault before Iga Swiatek punishes some more second serves, the pick of the points being a superb backhand winner down the line.
At break point, it looks like Swiatek is in control before an unforced error, and Podoroska takes advantage to secure the hold at deuce.
A bit of a let-off for Podoroska there.
*Osaka 3-1 Siniakova
It's a break to love for Naomi Osaka.
Katerina Siniakova can't live with the power and precision from her opponent and this already looks like it's going to be a tough match for her.
Osaka 2-1 Siniakova*
Image source, Getty ImagesKaterina Siniakova continues to struggle on her first serve, and double-faults for the first time.
Naomi Osaka follows that up with a brilliant forehand winner, and a miss from Siniakova brings up three break points.
Osaka 2-1 Siniakova*
Another excellent service game from Naomi Osaka. While she does concede a first point here, Osaka's accurate serving is denying Katerina Siniakova any encouragement in these early stages.
Swiatek 6-3 2-0 Podoroska*
Iga Swiatek faces little trouble consolidating that break of serve as she holds to 15, sealing the game with yet another forehand winner.
