So Venus Williams will face compatriot Sloane Stephens in the semi-final, meaning at least one American is guaranteed a place in Saturday's final.

But with Madison Keys and Coco Vandeweghe also through to the last eight, there is the prospect of an all-American semi-final line-up.

There's another men's quarter-final to come tonight, as Sam Querrey faces Kevin Anderson, but it's bed time for us.

We'll be back tomorrow from 17:00 BST for Vandeweghe against Karolina Pliskova, before the small matter of Roger Federer and Juan Martin del Potro.

We'll catch you then.

More from Venus Williams, who is the second of potentially four American women into the semi-finals: "I would love the top four, five to be that (American) again. That would be huge.

"When situations get hairy and it's crazy out here, I try to tell myself to enjoy the competition and enjoy the battle."

That was really something.

Petra Kvitova waves goodbye to the crowd and heads down the tunnel towards the locker room.

Venus Williams takes to the mic: "I have to say I felt every single one of you guys behind me, all 23,000. I didn't want to let you guys down.

"Everything she has gone through is unbelievable. It's wonderful to see her back and playing. I was so excited to see her playing well, to be able to play her. I hope we have more matches like that."

Image source, Getty Images

Jeff Tarango
Former professional tennis player on 5 live sports extra at Flushing Meadows

Kvitova played a great match but Williams was just too good in that tie-breaker

Williams double faults!

Deep breath, but a whole lot of net for Kvitova on her first serve... and on the second.

Match point Williams. Five of them.

Forehand long - oh so long - from Petra Kvitova. It's slipping away from the Czech.

Kvitova needs something on Williams' serve. The first is wide, the second pushes the Czech wide and Williams wins the rally.

Superb down the line forehand from Venus curves in - Kvitova can't get that back.

Another big serve from Kvitova and an even bigger passing backhand... but that's long, what a return from Williams.

Williams nets the return. 1-1.

It's Venus first up. She steadies herself and then cracks a quicken into the net.

Take two. That reaches its destination but can't beat Kvitovam but the Czech goes long.

Jeff Tarango
Former professional tennis player on 5 live sports extra at Flushing Meadows

After all this time, all this effort, we're going into a tie-breaker. This is where you have to put away the pain, put away the doubt and just swing.

We're going to a tie-break...

Jeff Tarango
Former professional tennis player on 5 live sports extra at Flushing Meadows

I think Venus likes the quick pace between points.

Petra Kvitova, serving to stay in the match for a second time.

Williams musters a response to the big Czech serve and engages Kvitova in a rally that the American comes out on top in. But the veteran can only guide her next return beyond the baseline.

It's breathtaking stuff as Kvitova continually clings on, before Venus finds the net. 30-15.

Fault. Let. Second serve. Pressure on for Venus.

She tosses one skywards, then changes her mind. Kvitova fires a punishing return back when the serve finally arrives, but it's long.

Williams holds.

Image source, Getty Images

Jeff Tarango
Former professional tennis player on 5 live sports extra at Flushing Meadows

This is high quality tennis, there hasn't been an error in three and a half games.

Amid all the fantastic strokes and perfectly-placed returns, it's a net ball that hands Venus the chance to take control of her service game.

She doesn't need a second invitation to slam a forehand deep beyond the grasp of Kvitova.

But the American overcooks a similar attempt moments later, dragging a backhand wide.