Federer beats Youzhny 6-1 6-7 (3-7) 4-6 6-4 6-2
Rogers and Gavrilova play longest women's match in US Open history
World number one Pliskova beats Gibbs 2-6 6-3 6-4
Seeds Dimitrov and Berdych knocked out, Del Potro through
Day four of US Open at Flushing Meadows
Ka Pliskova 2-6 6-3 3-3 Gibbs*
We haven't seen much animation from Pliskova but she waves a fist as she seals her latest service game with her 11th ace.
That was a much easier game for the world number one. It was over in no time.
*Ka Pliskova 2-6 6-3 2-3 Gibbs
If Pliskova was on top at the start of this set, things definitely seem to be going the way of her American opponent now.
Gibbs must be 20cm shorter than her opponent but again she uses spin on her serve to good effect.
She doesn't look daunted as of yet on the biggest court in tennis.
Ka Pliskova 2-6 6-3 2-2 Gibbs*
Gibbs is frustrated as the chance passes her by. The final point is sealed with an ace which the American could do little about but it was errors on the previous two points which cost her.
No doubt the world number one Pliskova is nervous. Gibbs knows she needs to take the chances when they arrive.
Image source, Reuters*Ka Pliskova 2-6 6-3 1-2 Gibbs
Nicole Gibbs is buoyed by coming through that crucial previous game.
She does all of the attacking to level at 30-30 and create a slight opening. Another fist pump. She's in the zone.
Pliskova nets! A rally of 20 or so shots ends in tame fashion from the world number one.
Gibbs has another break point...
*Ka Pliskova 2-6 6-3 1-2 Gibbs
Outstanding! What nerve from Nicole Gibbs.
She plays a drop shot from deep in the court that lands close to the left side line on Pliskova's side. The world number one uses her long legs to pick the ball up though and plays a tricky cross court response. But the winner from Gibbs is brilliant. From off the court she goes around the net post and clips the line. Perfect.
That's just one point in a closely fought game. This is the highest quality we've seen from the pair. Both are going all out at each other.
The American yelps as she stays ahead. A big stare down the other end too...
Rublev 7-5 4-4 Dimitrov*
Andrey Rublev has got back on serve against Grigor Dimitov on Louis Armstrong and has just saved two break points. It gets better - a beautiful drop shot allows the 19-year-old to hold and level the second set at 4-4.
Image source, Getty ImagesKa Pliskova 2-6 6-3 1-1 Gibbs*
The world number one has definitely upped her game.
She races to 40-0 with the use of her big serve that crunches down from her 1.86m height plus a full-stretched arm.
Pliskova then seals the game with one of her best points of the match.
She calmly neutralises the attacking strokes from Gibbs before picking off the American as she approaches the net.
Mike Dickson
Daily Mail tennis correspondent on BBC Radio 5 live sports extra at Flushing Meadows
Pliskova seems to have stalled the momentum that was coming from the other side of the net. One of the factors is that it does appear that this court is pretty slow and I think that is having an impact on results and how matches are being played. There are a lot of unforced errors around. A lot of ex-pros I've spoken to feel it's too slow. I can't see it being much of a help to Federer. If there is something wrong with his back, a slow court is not going to be what he wants.
*Ka Pliskova 2-6 6-3 0-1 Gibbs
What has Nicole Gibbs got now? She was electric in the first set and a half until a slight wobble at the end of that set. Can she hold off the world number one's charge?
Pliskova is not happy with the line judge in this opening game of the decider as she puts a forehand straight onto the line but it's called out, only to be overruled. Still, Pliskova gets 30-30 and for the first time Gibbs looks tense.
Well played the American. A good serve is finished off at the net and the crowd get behind their player.
The world number 127 once again shows no sign of injury despite the heavy strapping on her thigh, bouncing around the court to a forehand to take an important opening game.
Image source, EPAKa Pliskova 2-6 6-3 Gibbs
Not the start to the game Pliskova was after. An error and a double fault and all of the world number one's momentum from breaking in the last game is gone.
Now is she break point down? The line judge calls out but Pliskova wants another look. Big moments. It's in! Crucial for the top seed.
That sees her to 30-30 and from there she takes the set with the help of a net cord.
We're going to a decider.
Image source, ReutersRublev 7-5 1-3 Dimitrov*
Grigor Dimitrov has the first break of the second set over on Louis Armstrong.
Simon Cambers
Tennis journalist at Flushing Meadows
Pliskova has a great expression when the ball just drifts wide of the line. She looks at the line in disgust, but doesn't challenge it.
*Ka Pliskova 2-6 5-3 Gibbs
First signs of pressure on Gibbs.
At 30-30 Pliskova decides she is just going to keep the ball in play and eventually the American nets. And again! Relief. Finally the world number one breaks.
She will now serve for this second set.
Piers Newbery
BBC Sport at Flushing Meadows
There's plenty of support for Nick Kyrgios out on court four as he returns to action 24 hours after his defeat by fellow Aussie John Millman. Kyrgios was badly hampered by a shoulder injury but said afterwards he would stick to his promise to play doubles with compatriot Matt Reid, and he's doing just that. He doesn't look too comfortable but the crowd are appreciative of his efforts at least.
About 10 metres away, Millman is playing his second-round match against Malik Jaziri on court five, which can't help Kygrios's mood.
Image source, BBC SportKa Pliskova 2-6 4-3 Gibbs*
Plenty of oooooos and ahhhhhhs from the crowd in Pliskova's latest service game but the best point ends in a groan as American Gibbs makes the error. There is no doubt whose side the crowd are on.
The world number one strides expressionless back to her chair after sealing the game by forcing Gibbs into an error. Can Pliskova up her performance as we head into the business end of this set?
*Rublev 7-5 1-2 Dimitrov
Andrey Rublev is one of the #NextGen players at this year's US Open, and he's never beaten a top 10 player before.
He claimed his first ATP title at the Croatia Open after being handed a place as a lucky loser, and he's ended Dimitrov's streak of winning 13 consecutive sets.
It's still on serve over on Louis Armstrong.
Gigi Salmon
BBC Radio 5 live sports extra commentator at Flushing Meadows
Nicole Gibbs' forehand is on fire. There's nothing Pliskova can do but try and avoid the forehand if she can.
Image source, AFP*Ka Pliskova 2-6 2-2 Gibbs
First serious signs of frustration from Pliskova.
She is beaten by a second serve from Gibbs, not even moving towards the ball, and throws her arms out in frustration. Gibbs is hitting powerful groundstrokes but I'm not sure the world number one is picking where her opponents serve is going.
Gibbs breezes through the service game and pressure is straight back on the Czech.
Ka Pliskova 2-6 3-2 Gibbs*
Remarkably Pliskova 'double-bageled' Nicole Gibbs the last time these players met but she is right in a battle now. Every service game is a struggle for the world number one due to errors on her part and winners from the American.
Pliskova just about manages to hold her serve thanks to some cheap points with the serve but she must be wondering how she's finding it so tough against a player ranked 126 places below her.
Menendez-Maceiras 2-6 0-2 Del Potro*
Things are going rather well for Juan Martin del Potro over on Grandstand Court.
Seven aces and a 92% success rate on his first serve helped the Argentine take the first set against Adrian Menendez-Maceiras, and he's got an early break in the second.
Image source, AFP