Karolina Muchova is on the brink of taking the first set but Naomi Osaka is not giving up.

She saves the first two of four set points.

Annabel Croft
Former British number one on BBC Radio 5 Live

There's been a flurry of unforced errors from Osaka. When it's really mattered, there's been hesitation and she's just lost control.

Harry Poole
BBC Sport at Wimbledon

Nice moment for Naomi Osaka there as the Court One crowd gave her huge support before she attempted to serve her way back into this tie-break.

It doesn’t have the desired effect, however, as she falls four points down.

Jiri Lehecka puts away a smash at the net to keep his hopes alive.

Change of ends now.

Naomi Osaka powers a forehand long and it's a double mini-break for Karolina Muchova.

The 10th seed is just two points from taking the first set.

Alexander Zverev grabs the mini-break.

And then a net cord goes against Jiri Lehecka on a return, dropping agonisingly the wrong side of the net for the Czech.

Zverev three points from a first ever Wimbledon quarter-final.

Karolina Muchova has the early mini-break but Naomi Osaka is in quickly to reach a drop shot and ensure things don't get any worse for her.

Chris Bradnam
Commentator on BBC One

Well done, Jiri Lehecka!

He will take on his first tie-break of the tournament. By comparison, Alexander Zverev has played five tie-breaks in this tournament and he has won four of them.

Naomi Osaka must feel like she's having to win these points two or three times over, such is the defence of Karolina Muchova.

She manages it, though, rifling a forehand winner down the line to hold.

To a tie-break we go.

Image source, get

An emphatic ace seals Jiri Lehecka's turnaround in that service game.

And we have a tie-break. Lehecka must win it to stay in the match but Alexander Zverev begins the breaker with a wonderful volleyed winner.

Todd Woodbridge
Former Wimbledon doubles champion on BBC One

When you play Alexander Zverev on this surface, you don't try to play through him because he likes to go deep. It is very hard to hit a ball past him, so you have to build your pressure by your approach.

We have seen Jiri Lehecka use the forehand down the line well with a measured shot. He has to hit that and come in, not try to hit the winner off that ball.

Once they are in the points though, Lehecka is looking the better player. He just hasn't been able to make enough decent returns to put pressure on Zverev's service games in this set.

Harry Poole
BBC Sport at Wimbledon

There was a quick apology from Karolina Muchova after that fortuitous net cord, before she swivelled to return to her baseline and puffed out her cheeks in relief as she looked up to the sky.

A big slice of luck in that game, which will frustrate Naomi Osaka even more as Muchova wriggles free again.

No time to dwell on that here though.

Finally, Alexander Zverev is able to make an impact against serve. Aggressive returning and hitting in rallies forces two Lehecka errors.

15-30... the German is two points from the quarter-final.

Oh but goodness what tennis from Lehecka, superb defensive play and then a point-winning delicate, delicious drop shot for 30-30.

Image source, Getty Images

Karolina Muchova survives.

A serve and volley gets her to advantage before Naomi Osaka is unable to return a big serve out wide.

Muchova has guaranteed at least a tie-break in this first set.

My prediction of a tie-break was looking ropey as Naomi Osaka went up 0-30 but Karolina Muchova battles back.

The Czech needs a bit of luck as she races in for a volley, gets it wrong but the ball hits the net cord and drops on Osaka's side of the net.

An apology follows but we all know she's not that sorry. No player is.

Osaka shrugs that off, though, and a double-fault hands her a break point. One that is snatched away by Muchova's booming forehand winner.

We're back at deuce. That prediction is still in the balance.

Alexander Zverev replies with a hold to love of his own.

Both players struggling to get any sort of consistent purchase on their returns - and that is a testament to the accuracy and quality of serving on show.

Again, Jiri Lehecka must serve to stay in the tournament.

For the third match in a row, Briton Henry Patten and Finnish partner Harri Heliovaara have come through a final-set tie-break to win!

They've beaten Guido Andreozzi and Manuel Guinard 2-6 6-4 7-6 (10-6) to reach the men's doubles semi-finals.

The 2024 Wimbledon champions will face Thanasi Kokkinakis and Aleksandar Kovacevic, who won their quarter-final in straight sets, as they bid to reach a fourth Grand Slam final as a duo.

Image source, Getty Images

Jiri Lehecka shows no sign of pressure of needing to serve to stay in the match.

Two superb serves set him up for a 30-0 lead. Another gives him the chance to unleash a forehand winner for 40-0.

Alexander Zverev gambles with a forehand close to the side line - but it's out. Another Lehecka hold to love - his serve has been amazing today.

Harry Poole
BBC Sport at Wimbledon

Naomi Osaka really got herself fired up with that booming backhand which almost took the racquet out of Karolina Muchova’s hands in the Czech’s previous game.

But she slammed the ball into the net in frustration after missing the line at 15-15, as her opponent escaped.

Both players are striking the ball beautifully and it’s a really high-quality contest.