US Open day nine - listen to BBC Radio 5 Live commentary (UK only)
LIVE: Two-time winner Naomi Osaka 1-6 second seed Elena Rybakina in fourth round
Rybakina will replace Aryna Sabalenka as world number one if she reaches last four
Six-time major champion Iga Swiatek beaten 7-5 6-3 by Olympic champion Zheng Qinwen
Swiatek has not got past last eight in New York since winning title in 2022
French Open champion Mirra Andreeva recovers from losing first set to defeat Anastasia Potapova and reach quarter-finals
*Osaka 1-6 3-3 Rybakina
This second set has been much more like what we all expected from this match.
The problem for Naomi Osaka is that the way the first set got away from her means there is no margin for error.
Elena Rybakina is looking pretty imperious on serve and holds again with ease.
Annabel Croft
Former British number one on BBC Radio 5 Sports Extra 2
Image source, Getty ImagesI am getting the sense that Osaka is getting a bit edgy and uptight here.
Osaka 1-6 3-2 Rybakina*
Danger is brewing for Naomi Osaka again at 15-30 but she keeps Elena Rybakina at bay.
An 11-shot rally could go either way but Osaka gets it done.
The break point does come, though. Forehand lasered cross-court for a winner. Unstoppable from Rybakina.
Once again, Osaka has to dig deep and a booming forehand of her own, that Rybakina can only put into the net, saves it.
A couple of big serves later and the two-time champion has secured the hold.
*Osaka 1-6 2-2 Rybakina
Image source, Getty ImagesElena Rybakina races into a 40-0 lead and another comfortable service game looks on the cards.
However, she struggles to get her first serve in from there and Naomi Osaka wins the next couple of points.
No panic from Rybakina, though, and despite another first serve going awry, the second proves good enough this time as Osaka's return sails long.
Osaka 1-6 2-1 Rybakina*
Image source, Getty ImagesThat's an important hold for Naomi Osaka.
Elena Rybakina continues to play with such confidence, making everything look so easy, and brings up a break point.
But Osaka slaps an ace down the T to draw the biggest cheer of the match so far from the crowd.
From there the Japanese star comes through, showing great resolve. A couple of unforced errors from Rybakina will give Osaka encouragement too.
Annabel Croft
Former British number one on BBC Radio 5 Sports Extra 2
This is just relentless from Rybakina, there is just no let up. She is getting such good direction on the ball and at the moment Osaka cannot keep up with it.
*Osaka 1-6 1-1 Rybakina
Elena Rybakina is giving Naomi Osaka the runaround at times here.
She's hitting the ball so well, so accurately, moving her opponent side to side and Osaka is doing well to keep the points going as long as she is.
A double fault helps it get to 30-30 but Rybakina shuts the door, coming in behind a big serve to slap a forehand winner into the corner.
Osaka 1-6 1-0 Rybakina*
The crowd in New York are right behind Naomi Osaka and have been since the start of this match but they had gone a little quiet.
Like the rest of us, they were likely just shocked by how quickly that first set unravelled for the four-time major winner.
There's more noise on Louis Armstrong now, though, as Osaka gets up and running in the second set with a hold to 15.
Cerundolo 3-6 6-4 5-7 0-0 Blockx*
Image source, EPAThat hold of serve by Alexander Blockx from 0-40 down in the previous game is looking absolutely massive now... because he's broken Francisco Cerundolo in the next game to win the third set.
Cerundolo saved one break point with an ace but double-faulted on a second moments later, so the Belgian moves one set away from the quarter-finals.
*Osaka 1-6 0-0 Rybakina
Annabel Croft
Former British number one on BBC Radio 5 Sports Extra 2
Rybakina is not giving Osaka any chance to breathe out there today. She is taking all of the time away and stamping all of the authority, she is in control.
I was expecting this to be a really long drawn-out affair.
But that was all one-way traffic and there was no way Osaka could do anything against the tennis that Rybakina has brought to this match.
*Osaka 1-6 0-0 Rybakina
Image source, Getty ImagesElena Rybakina smashes down an ace out wide to take the first set in a little more than 20 minutes.
Who saw this coming?
It's all looked very straightforward for the second seed from Kazakhstan.
There has been the odd point here and there where Naomi Osaka has looked like herself, showing that power and quality, but for the most part, she's looked well off it.
*Cerundolo 3-6 6-4 5-6 Blockx
A big moment towards the end of the third set on Arthur Ashe Stadium as Alexander Blockx, serving at 5-5, recovers from 0-40 down to hold serve and guarantee himself at least a tie-break.
Osaka 1-5 Rybakina*
Annabel Croft
Former British number one on BBC Radio 5 Sports Extra 2
Osaka is targeting that forehand but Rybakina is hitting the ball so beautifully.
Osaka 1-5 Rybakina*
Goodness me. In the blink of an eye, Elena Rybakina has taken charge and will serve for the first set.
She brings up three break points with some brilliantly crisp groundstrokes, sending the ball deep into the corners time and again.
Naomi Osaka saves the first but hits a backhand into the net on the next and Rybakina has the chance to wrap up the set in the next game.
*Osaka 1-4 Rybakina
Image source, Getty ImagesElena Rybakina consolidates the break but was made to work for it.
She swiftly goes up 30-0 but Naomi Osaka fights back with some powerful striking from the baseline.
The Japanese 13th seed earns her first break point but it's gone in a flash as Rybakina hammers down an ace.
A backhand thumped down the line secures the hold.
Osaka 1-3 Rybakina*
Image source, ReutersA real gift from Naomi Osaka.
Three double faults in the game to hand Elena Rybakina a break of serve.
The second seed had to do precious little to earn it as her other point came when Osaka sent a forehand wide.
*Osaka 1-2 Rybakina
Image source, ReutersAnother convincing hold of serve, this time for Elena Rybakina.
Both players have settled well on serve early on.
Naomi Osaka comes out on top in the only rally of more than a couple of shots with Rybakina otherwise managing to keep the points short.
Osaka 1-1 Rybakina*
Annabel Croft
Former British number one on BBC Radio 5 Sports Extra 2
I think it will be fascinating mentally, how much this match will get to Rybakina.
*Cerundolo 3-6 6-4 3-4 Blockx
Image source, ReutersThere are also fourth-round matches taking place in the men's singles at the US Open today.
Argentina's Francisco Cerundolo, who fought back from two sets down to beat Taylor Fritz in the previous round, dropped the first set against Belgium's Alexander Blockx on Arthur Ashe Stadium but won the second to level at one set all.
Elsewhere, unseeded pair Arthur Gea and Botic van de Zandschulp will soon be getting their fourth-round match under way on Grandstand, with top seed Alexander Zverev a potential quarter-final opponent for the winner.
Zverev plays Luciano Darderi in the night session, while home favourite Learner Tien will take on Karen Khachanov after the Osaka-Rybakina match concludes on Louis Armstrong Stadium.
Osaka 1-1 Rybakina*
Image source, ReutersSimple as you like for Naomi Osaka.
She gets herself on the board with a hold to love in double-quick time.
