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Rafael Nadal beaten by Frances Tiafoe 6-4, 4-6, 6-4, 6-3
World number one Iga Swiatek beats Jule Niemeier 2-6 6-4 6-0
Swiatek will play Jessica Pegula who defeated Petra Kvitova 6-3 6-2
Cameron Norrie loses 6-4 6-4 6-4 to Andrey Rublev in last 16
Collins v Sabalenka followed by Cilic v Alcaraz in night session (midnight UK)
Day eight of final Grand Slam of year at Flushing Meadows
*Swiatek 2-6 6-4 2-0 Niemeier
That's five successive breaks of serve for Iga Swiatek who takes an early lead in the final set.
It looks like the occasion is getting the better of unseeded Jule Niemeier. The world number one is well on top.
Nadal 4-6 5-4 Tiafoe*
Ah, Tiafoe roars to the heavens as an over-eager backhand allows Nadal to get himself to safety.
It's close. But Nadal is now one break of serve from levelling this match.
*Nadal 4-6 4-4 Tiafoe
Oh dear. Another double fault from Rafael Nadal.
He's not pleased with himself one bit. The crowd, on the other hand, are getting more and more excited.
Deuce, from 40-0.
*Nadal 4-6 4-4 Tiafoe
A deadly forehand from Rafael Nadal puts him in charge on serve, before Tiafoe eventually falters as he scrambles from side to side to keep the point alive.
At 40-0, Nadal produces only his second double fault - and that's followed by a fizzing forehand down the line from Tiafoe...
*Nadal 4-6 4-4 Tiafoe
And that is a very, very nice hold to love from Frances Tiafoe.
No chances for Rafael Nadal here!
The crowd are getting right behind him, but he's remaining calm and focused. Huge games coming up.
Jonathan Jurejko
BBC Sport at Flushing Meadows
While Niemeier nips off court, the camera operatives on Armstrong amuse themselves by basically pressuring a fan to chug a beer.
The woman looks like she was enjoying a refreshing sip of her crisp lager - then the camera lingers.
That forces her into sinking the whole glass while the crowd eggs her on.
Eventually she gets there and draws one of the biggest cheers of the afternoon.
Kudos. I've been there on stag dos - without 14,000 people watching. Not a pleasant place to be.
Nadal 4-6 4-3 Tiafoe*
Laura Robson
Former British number one at Flushing Meadows
The longer this goes on I almost back Tiafoe, with Nadal not getting a break of serve.
Nadal 4-6 4-3 Tiafoe*
Ace number three for Rafael Nadal for a confident start to his latest service game.
And still no hint of a break point in this second set as the Spaniard ticks off another hold. Can he find one next?
*Nadal 4-6 3-3 Tiafoe
Efficiently done once again by Frances Tiafoe. He leaves Rafael Nadal chasing shadows as he follows up a backhand winner with a final forehand. On we go on serve in set two...
Nadal 4-6 3-2 Tiafoe*
A good return from Nadal draws the error from Tiafoe for the first point on the American's serve, but the second seed is unable to apply the pressure as he makes a big miss which seems to confuse even himself.
Image source, ReutersNadal 4-6 3-2 Tiafoe*
Laura Robson
Former British number one at Flushing Meadows
I am expecting a comeback from Nadal but I do wish I understood Spanish so I could understand what is being said.
He is winning his service games very easily, but still not getting a really good read of where his game is at.
Swiatek 2-6 6-4 Niemeier
This set was always going to be won with a break as Swiatek gets over the line thanks to a Jule Niemeier error.
The last eight games of the second set saw seven breaks of serve.
This match has got so, so scrappy, but that will suit the top seed who is back level. We go to a decider on Louis Armstrong Stadium.
Nadal 4-6 3-2 Tiafoe*
Boom. A big ace from Rafael Nadal to kickstart this latest game. It appears he is managing to block out whatever was bothering him towards the end of the opening set for the time being.
Another ace takes him to 40-0 and a Tiafoe miss sees the Spaniard edge 3-2 up.
Swiatek 2-6 5-4 Niemeier*
An extraordinary second set as a sixth service game is broken, this time Swiatek can't hold while serving for the set.
Can Jule Niemeier finally end this breaking run?
*Nadal 4-6 2-2 Tiafoe
Frances Tiafoe is still going strong. The American moves to 40-0 as he continues to fire on serve and completes the job to 15 by guiding a sweet forehand down the line.
Image source, Getty Images*Swiatek 2-6 5-3 Niemeier
David Law
Commentator on BBC Radio 5 Live
We have an intriguing state of affairs. With Swiatek leading Niemeier, Niemeier was asking the crowd for their love.
They gave it. Swiatek looked miffed.
*Swiatek 2-6 5-3 Niemeier
Both players are struggling on their own service game on Louis Armstrong Stadium.
First Jule Niemeier breaks top seed Iga Swiatek to split the defecit and go 3-4 down in the second set.
But then Swiatek hits back with a break of her own and she'll be serving for the set next game.
*Nadal 4-6 2-1 Tiafoe
Terrific point. Tiafoe leaves Nadal with nowhere to go before nonchalantly tapping a volley back over as he gets up and running on the Spaniard's serve.
But Nadal takes charge from there, and seems to be hitting his serves a bit more freely. He lets out a huge roar as he polishes that game off with a forehand winner.
Image source, Getty Images*Nadal 4-6 1-1 Tiafoe
David Law
Commentator on BBC Radio 5 Live
Nadal has had two matches that he has looked sub-standard. His third round was much better but Gasquet is hardly an opponent that has caused him problems.
But he is one of the great players at finding a way through, somehow.
*Nadal 4-6 1-1 Tiafoe
Laura Robson
Former British number one at Flushing Meadows
We can just hear how much chatter is coming from Nadal's player box. I feel like this week they have been louder than ever,