Williams beats Kvitova 6-3 3-6 7-6 (7-2) to reach semi-finals
Roof closed during second set on Arthur Ashe Stadium
Stephens beats Sevastova 6-3 3-6 7-6 (7-4) to make last four
Carreno Busta beats Schwartzman 6-4 6-4 6-2 to make men's semis
Stephens 6-3 3-6 2-3 *Sevastova
Sloane Stephens with a drop-volley that lands on the court like a butterfly on hot sand.
Beautiful soft hands. That is 0-30.
Anastasija Sevastova over-cooks a lob and that is 0-40 and three break-back points for Stephens.
Stephens 6-3 3-6 2-3 *Sevastova
Jeff Tarango
Former professional tennis player on 5 live sports extra at Flushing Meadows
There's 17,000 people rooting for Sloane Stephens.
It's a big forehand from Sloane and an even bigger 'come on!' from the American.
Image source, Getty ImagesStephens 6-3 3-6 2-3 *Sevastova
Sloane Stephens punches away her backhand down the line, landing plum on the whitewash to finally snuff out the danger.
She still trails by the break though.
#bbctennis
Rose Richards: Sloane not serving well. Ana steady and sure.
*Stephens 6-3 3-6 1-3 Sevastova
Sloane Stephens with a nothing shot, slicing down the middle of the court and long to give Anastasija Sevastova a look at 30-30.
A nervy second serve lands.
And Stephens throttles her forehand into the net.
Is the jig nearly up?
Not just yet. Break point saved as Sevastova slices into the net...
Deuce.
*Stephens 6-3 3-6 1-3 Sevastova
Jeff Tarango
Former professional tennis player on 5 live sports extra at Flushing Meadows
Anastasija Sevastova is showing Sloane Stephens she believes she can win this match.
I don't think we have seen the last of Stephens, I think she has a third wind. There is a lot of tennis to be played.
Image source, Getty Images*Stephens 6-3 3-6 1-3 Sevastova
Anastasija Sevastova is purring, Sloane Stephens is spluttering on vapours.
The Latvian has 40-0 and is helped over the finish line in the game as Stephens cracks a very makeable smash towards the front rows without making the requisite dot-down on the blue court.
Stephens 6-3 3-6 1-2 *Sevastova
Sloane Stephens hits a superb off forehand to wrong-foot Anastasija Sevastova and pull back to 15-30, but she is fighting against a tide of her own increasing error count.
Two break points.
The American attacks to see off the first.
She misses with her first serve on the second.
And then Sevastova uncorks a forehand of rare vintage, the ball zipping away to put her firmly in the driving seat for the match.
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*Stephens 6-3 3-6 1-1 Sevastova
Anastasija Sevastova holds to 15 and with plenty to spare.
Taking the first two games of the decider as a sample, it is looking like the mojo is with Sevastova.
Image source, ReutersStephens 6-3 3-6 1-0 Sevastova*
Jeff Tarango
Former professional tennis player on 5 live sports extra at Flushing Meadows
All eight players in the women's quarter-finals feel like they have a chance to win the tournament.
You get more scared, because it's not just the match on the line.
Stephens 6-3 3-6 1-0 *Sevastova
The Arthur Ashe crowd rouse themselves to a supportive ripple of applause as Sloane Stephens double faults to 15-30 down.
A grim-faced stare into the strings from the American.
She seems to have found whatever she was looking for in the cat-gut.
Two big bolshy forehands take the next two points away from Anastasija Sevastova and Stephens is home and hosed in that game.
There is no margin for error now though for either woman. This match is teetering on the watershed.
Image source, EPA*Stephens 6-3 3-6 Sevastova
Jeff Tarango
Former professional tennis player on 5 live sports extra at Flushing Meadows
The New Yorkers have changed, having gone so long without American success on the men's side, they have been deep on the women's side with the Williams sisters but there's not much else to cheer about.
They have become an international crowd. They cheer for someone who is most like a New Yorker, someone who gets up at 3am and grinds out their day.
*Stephens 6-3 3-6 Sevastova
Not a lot of noise on Arthur Ashe as Anastasija Sevastova levels up the match and the hometown fans look forward a little apprehensively to a deciding set.
It is the Latvian who is coming into the home straight with all the momentum.
Image source, AFPStephens 6-3 3-5 *Sevastova
Jeff Tarango
Former professional tennis player on 5 live sports extra at Flushing Meadows
Anastasija Sevastova was so hard on herself serving for the match against Maria Sharapova, so if it's escalated 10% it's going to be a hot one.
Stephens 6-3 3-5 *Sevastova
Anastasija Sevastova bosses the first point from the back of the court on the forehand wing.
That is supposed to be Sloane Stephens' trick.
The American shows she still has those sort of shots under her top hat, whipping inside out and in.
Sevastova misses a chance on return at 15-30 up. Stephens rushes the net to spook her out of the game.
Sevastova makes a Harry Enfield 'calm down, calm down' gesture towards her box. She serves for the set next...
Image source, AFP*Stephens 6-3 2-5 Sevastova
Jeff Tarango
Former professional tennis player on 5 live sports extra at Flushing Meadows
I started saying about how this match was two players coming from different directions, one who is constantly trying to keep herself fired up and one who is constantly trying to calm herself down.
It's going to be really interesting.
*Stephens 6-3 2-5 Sevastova
Another chance disappears down the gurgler for Sloane Stephens.
She needs to pull back hard and fast on the joysticks to keep this set alive.
Stephens 6-3 2-4 *Sevastova
Sloane Stephens sees off another break point with a serve right up on the paint, skidding through around Anastasija Sevastova's throat.
The American closes out to keep just a break back in this second set.
Stephens glowers up to her box and gets an animated show of clenched fists and nodding heads in response.
*Stephens 6-3 1-4 Sevastova
Jeff Tarango
Former professional tennis player on 5 live sports extra at Flushing Meadows
It's a flip-flop from the first set where Sevastova had a chance to get back into the set and didn't.
It's the perfect temperature outside for tennis. The players aren't getting worn down, it's just what's on the line for their careers.
Stephens is clearly doubting herself and taking a little extra time to look for support from the people in her box.
Image source, Getty Images