Summary

  • Serena Williams beats Karolina Pliskova to reach semi-finals

  • American 17th seed wins 6-4 6-3 at Flushing Meadows

  • Argentina's Juan Martin del Potro through to semi-finals on Friday

  • Third seed beats John Isner 6-7 (5-7) 6-3 7-6 (7-4) 6-2

  • 2017 champion Sloane Stephens knocked out by Anastasija Sevastova

  • Latvia's Sevastova through to semi-finals with 6-2 6-3 victory

  • Rafael Nadal plays Dominic Thiem in the last match of day nine

  • Extreme heat policy in place as New York temperature causes problems

Live Reporting

Saj Chowdhury and Matthew Henry

  1. Williams breaks back

    *Williams 4-4 Pliskova

    Williams takes her chance.

    She's not at 100%, not even 80% but she's dug deep and got the break.

  2. *Williams 3-4 Pliskova

    Break point as Pliskova looks for the pass down the line but finds the net instead.

  3. *Williams 3-4 Pliskova

    An energetic 12-shot rally ends with Williams slapping a forehand away.

    30-30.

    Becoming interesting again.

  4. *Williams 3-4 Pliskova

    Williams launches a flat forehand which gives her the edge in this game.

    Pliskova takes off the edge with a good serve.

    Another serve that kicks up into Williams is returned high and long.

    30-15.

  5. Williams 3-4 Pliskova*

    She holds as Pliskova fires wide.

    The Czech player still has that crucial break.

    Now would be a good time for Williams to strike.

  6. Williams 2-4 Pliskova*

    Williams' sister Venus, who isn't bad at tennis either, looks a little concerned in the camp.

    0-15.

    Her younger sister lessens the need for concern with a great one-handed angled forehand.

    15-15.

    30-15.

    A big serve brings Williams to within game point.

  7. Jonathan Jurejko
    BBC Sport at Flushing Meadows

    The first time Pliskova's serve has come under pressure today. Serena only won two points in the first two service games for the Czech.

    Williams is not happy out there. She's constantly clasping the sticky air with her hands in frustration, looking up to her box for answers she can't solve at the moment.

  8. *Williams 2-4 Pliskova

    Williams wastes one chance by going long with a forehand.

    And goes long with the second as Pliskova delivers a good kicking second serve.

    Pliskova eventually holds.

  9. *Williams 2-3 Pliskova

    Did the failure to take her break-point chances rattle Pliskova?

    0-15.

    15-15.

    Then Pliskova goes long - it's 15-30 on her serve.

    The world number eight makes another error as she goes long once more.

    Two break-back points.

  10. Williams 2-3 Pliskova*

    Williams finally holds - that game itself was a tough workout in this heat and humidity.

    *denotes next server

  11. Jeff Tarango
    Former professional tennis player at Flushing Meadows

    Roger Federer struggled in his new attire last night, sweating buckets, I wonder if Serena has actually practiced with her tutu on. It seems to be disturbing some part of her balance.

  12. Williams 1-3 Pliskova*

    Break point three as Williams pulls her shot wide.

    But she saves again as Pliskova returns long.

    Williams then sends the Czech player wide who can only fire back into the green at the back of the blue court.

    Advantage Williams.

  13. Jonathan Jurejko
    BBC Sport at Flushing Meadows

    Ashe sensed danger for their hero there. A galvanising cheer goes up as Serena, pausing on the baseline for the noise to subside, finds herself 30-0 down.

    That does the trick. Two big serves follow as she levels to take the game into deuce....

  14. Williams 1-3 Pliskova*

    Williams works hard to win the next point as she rushes in to slap home a winner.

    That is undone by a long backhand.

    A 15th unforced error by the 23-time Grand Slam singles champion.

    Williams then lands a shot out of bounds.

    Break point.

    Saved as Pliskova goes long.

    Deuce again.

  15. Williams 1-3 Pliskova*

    Williams produces her second double fault, but follows it up with a third and fourth ace.

    30-30.

    A wayward forehand from Williams lands horribly wide.

    30-40.

    A big serve gets her out of a tricky spot - for now.

    Deuce.

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

    Most people have come for the Serena Williams Show and it has fallen pretty flat so far.

  17. *Williams 1-3 Pliskova

    Latecomers!!!!

    People arriving late on Arthur Ashe with the game about to get under way - it's been a theme during these two weeks.

    It doesn't seem to bothering Williams who has enough problems of her own.

    Pliskova produces a brilliant pick-up then a great angled shot.

    30-0.

    40-0.

    Williams then returns long to a silent Arthur Ashe.

  18. Jonathan Jurejko
    BBC Sport at Flushing Meadows

    Predictably everyone is piling in during the first changeover. The gangways are busier than Grand Central station. Serena needs all the support she can get.

  19. Jeff Tarango
    Former professional tennis player at Flushing Meadows

    Serena is used to a player playing further back. Pliskova is standing on the baseline and doesn't give any ground. The ball is coming back quicker than she is used to.

  20. Jonathan Jurejko
    BBC Sport at Flushing Meadows

    Rushing from the media centre, based in the bottom south-west corner of Ashe, to the on-court seats on the lower tier is not advisable for someone carrying a laptop, phones, wifi access and notes.

    That's because the New York crowd like to leave it late before streaming into the world's biggest tennis stadium.

    Fans pile through the gates, and up the stairs and escalators, like football fans filing in for kick-off at 2.55pm.

    Still plenty of empty seats though as, I'd imagine, they grab another Honey Deuce cocktail (the US Open equivalent of Pimm's) before settling in.

    US OpenBBC Sport