Emma Raducanu underwent surgery on her ankle last year and her movement looks on point as she strides to the net to return a drop shot with one of her own. 30-15 to the Brit.

That's as good as it gets in the third game, though, with Renata Zarazua going on to hold.

BBC iPlayer

Image source, PA Media

You can watch BBC TV coverage and listen to BBC Radio 5 Live commentary by clicking on the "Watch and listen" option at the top of this page.

You can also find streams of every court on the BBC iPlayer.

Jonathan Jurejko
BBC Sport at Wimbledon

Tell you what... Renata Zarazua doesn't seem too fazed by the situation.

The Mexican lucky loser only found she was playing this morning - against a British former Grand Slam champion on Centre Court at that.

But she has started confidently, getting loads of balls back and showing some deft touches.

Oh my! That was some rally as Renata Zarazua takes a 30-15 lead. Zarazua and Raducanu exchange backhands what seems an eternity before the Mexican eventually digs out a lovely lob as Raducanu comes to the net to return a drop shot.

Raducanu shows character to fightback and gets on the board with her first hold of serve.

Naomi Osaka breezed through the first set but since then it's been an uphill battle.

We've had three games in this set so far and all have been breaks of serve.

Osaka is sat down at the break with her towel on her head.

Image source, PA Media

Daniel Altmaier is unable to convert two set points and Arthur Fery makes him pay as he breaks at the third opportunity.

The German will still be confident of forcing a fifth set but Fery has just put a grain of doubt into his mind.

Jonathan Jurejko
BBC Sport at Wimbledon

While most of the Royal Box dignitaries go for a salmon and dill sandwich (or whatever is served up there), David Beckham and his mum Sandra have remained on the front row.

And their love for their game is rewarded by that whopping forehand return from Raducanu in the first point.

Marker laid.

A huge roar as Emma Raducanu sends a forehand down the line to make an early statement. 15-0.

You do have to wonder how mentally prepared Renata Zarazua is for the match. The Mexican, a lucky loser, only got a late call and she's now making her Wimbledon and Centre Court debut against a British hope!

Well, Zarazua is not over-awed by the occasion as she holds with a beautifully executed drop shot to see out the game.

The umpire has just asked a member of the crowd to move their beer.

We think it's because it's very close to the court and could be taken out by a flying ball.

Meanwhile Osaka breaks back to add to the drama.

Image source, PA Media

Earlier, we told you that world number three Aryna Sabalenka had pulled out of Wimbledon with a shoulder injury.

The same fate has befallen Victoria Azarenka, who was scheduled to play Sloane Stephens on court two later, but she has had to withdraw.

Charlotte Coates
BBC Sport at Wimbledon

There’s been a huge shift in momentum on court 16 and Daniel Altmaier is moving swiftly towards taking this fourth set and forcing a decider.

Arthur Fery looks as though his energy has depleted hugely and he’s been coming over to his team, who are sat to my right, and shaking his head.

Image source, BBC Sport

"End of warm-up" is the call from the umpire's chair and we are set to get under way with this match in front of a packed crowd on Centre Court.

Diane Parry has broken again early in the set and this time it could be crucial.

Osaka slammed the ball into the net from close range. Is she starting to panic?

Image source, Getty Images

Raducanu missed the clay-court French Open to focus on being fit and ready for the British grass season - and the move looks to have paid dividends.

Reaching the Nottingham semi-finals was followed by a run to the Eastbourne quarter-finals, including a win over American world number five Jessica Pegula.

"I think I'm in a really good place," said Raducanu, who plays against Mexican lucky loser Renata Zarazua.

"I did a good chunk of work at the end of the year to get back and healthy. I've continued that work throughout this year.

"I feel good in my body. There are no doubts."

The 21-year-old has just stepped on to Centre Court as she prepares to make her first appearance at SW19 since suffering a second round exit in 2022.

Over on Court 12, Britain's Liam Broady has been broken for the third time to lose the first set against Botic Van De Zandschulp of the Netherlands.

Broady went 4-0 down before getting on the board with a break of his own.

However, Van De Zandschulp broke the Stockport man again to clinch the opening set.

Jonathan Jurejko
BBC Sport at Wimbledon

Image source, BBC Sport

As you would expect, it is the warmest of welcomes for Emma Raducanu as she makes her return to Centre Court - including a few Union Jacks waved in solidarity.

The 21-year-old is back in one of British sport's iconic venues having missed last year's Wimbledon because of injuries.

Last time she played here was a straight-sets defeat by France's Caroline Garcia two years ago.

Raducanu, who has cut a happy and relaxed figure in recent weeks, beams as she walks out to generous applause.

Another ovation greets her bounding out to the baseline for the warm-up.

Here come Emma Raducanu and Renata Zarazua on to Centre Court.

The pair get their final instructions from the umpire and Raducanu hands the first service to her Mexican opponent after winning the coin toss.

They are reminded "it's grass-court season, so no damage to the turf will be tolerated" and rightly so, the surface is looking in fine shape as they go through their warm-up.

Wow. Naomi Osaka was 40-15 up and somehow lost her service game when serving at 4-1 down.

She was soon out of challenges too and Diane Parry held to take the set 6-1.

We're into a decider.

Image source, Getty Images

We've got a jam-packed summer of sport from Euro 2024 to Wimbledon to the Olympics.

Emma Raducanu was seen showing support for the Three Lions yesterday, sporting the England Euro 2024 shirt, just hours before Jude Bellingham and Harry Kane scored late goals to book a place in the quarter-finals at the expense of Slovakia.

Jonathan Jurejko
BBC Sport at Wimbledon

We're a minute or so away from Emma Raducanu stepping through the sliding doors onto Centre Court.

A lot of fans have popped off for a comfort break, but there is still a palpable buzz of excitement.