Meanwhile, on court 16, Great Britain's Jan Choinski is into a two-set lead against Czech player Vit Kopriva.

After breaking to take a 6-5 lead, Choinski was 0-40 down but recovered to hold serve and move within one set of the second round.

Amy Lofthouse
BBC Sport at Wimbledon

Image source, Getty Images

The Williams sisters - who will team up again for the doubles here - are synonymous with Wimbledon.

For a 19-year period, at least one Williams sister was in all but four singles finals at SW19. They won a combined 12 Wimbledon singles titles - seven for Serena and five for Venus - between 2000 and 2016. Elder sister Venus won it first. Little sister Serena won it more.

When they combined they were dominant, winning six women's doubles titles together. When they faced one another it was absorbing - two players who knew each other's games inside out, from years spent on the practice courts in Compton, California.

If you think of the Williams sisters you see them in the Wimbledon whites, moving around a grass court, two beautiful service motions, with athleticism, power, and touch at the net to boot.

As Serena said - it is not every day Wimbledon holds a wildcard for someone.

"I can name probably like a handful of people. I happened to be one of them," she said.

"I thought, 'I should really take this opportunity'. Who knows if I'll ever make it here again? This could be it.

"I was like, 'What's wrong with you, Serena? What are you thinking? Are you nuts?' I have this great opportunity to showcase what I do best."

Will her age and all that comes with it - being half a step slower out of the corners of the court, having to conserve more energy the longer a match goes on - be too tough to overcome?

Or will her aura, the sheer sense of simply just being Serena Williams, be enough to carry her through the opening round at least?

David Quayle, Williams' British hitting partner who helped her prepare for her return in the doubles at Queen's earlier in June, says it is "hard sometimes not to feel a little bit nervous" around Williams.

"It's a funny thing to see someone that you have watched their serve on TV for so many years, and then all of a sudden that serve is coming at you," he told BBC Sport in June.

"You're fighting between admiring some of the shots and actually playing them. She's got that kind of aura.

"I'm starting to getting a little bit more used to seeing her over the other side of the net, but every day is special."

When Maya Joint was born in April 2006, Serena Williams had already won seven of her 23 Grand Slam singles titles.

But the 44-year-old is not be the oldest player to feature in a women's singles draw at Wimbledon in the Open Era, with Martina Navratilova returning to the grass courts aged 47 years and eight months in 2004.

Navratilova became the oldest player to win a singles match in the Open Era when she beat Catalina Castano 6-0 6-1 in just 46 minutes before bowing out in round two.

Can Williams match that?

Emily Salley
BBC Sport at Wimbledon

It's absolute chaos in the Centre Court corridors.

Plenty of fans have stayed stuck to their seats after Alexander Zverev and Alexander Blockx's four setter, afraid to miss out on Serena Williams' impending entrance.

Those that have left are running around like headless chickens, trying to make a last-minute dash for the toilets or grab a quick snack.

Serena Williams is playing in the women’s singles at Wimbledon for the 22nd time after making her debut in 1998.

The American is a 23-time Grand Slam singles champion, including seven Wimbledon titles. Her most recent crown at SW19 came in 2016, with back-to-back final defeats in 2018 and 2019.

She’s also won six women’s doubles titles at Wimbledon (among 14 majors) and one mixed doubles titles (two overall).

The 44-year-old will become the fourth-oldest player to appear in the women’s singles main draw at a Grand Slam in the Open Era and the second-oldest behind Martina Navratilova (2004).

Williams holds the record for most women's singles Grand Slam match wins in the Open Era, with 367 victories.

Image source, BBC Sport

Jamie Murray
Seven-time Grand Slam doubles champion on BBC One

Maybe Serena Williams came back because she didn't believe Novak Djokovic could get to 25 Grand Slam titles and she thought someone else needs to do it!

I'm so intrigued to see what level she is going to bring to the court today. She hasn't played for four years and she is playing on one of the most iconic courts in the world, so it is a very unique situation. It feels like the whole world is watching to see what she is going to bring to the table.

She has to be nervous. There is no way she is walking out here full of confidence. I don't care how well her practice has gone, until you hit your first ball out there in anger you don't know what you can bring to the table.

Tim Henman
Former British number one on BBC One

It is just the unknown for Serena Williams. She is one of the greatest champions in all of sport and she is coming back at the age of 44 years old, so what's going to happen? We don't know.

The intrigue around this third match on Centre Court is just unbelievable.

Four weeks is quite a long time to be away from playing, four months seems an absolute age, and then you have Serena coming back after four years - and at Wimbledon on the biggest of stages. It is going to be epic.

• Aug 2022 – Williams announces she is “evolving away” from tennis after the US Open
• Oct 2025 – Williams re-enters the International Tennis Integrity Agency's registered drug testing pool, opening the door for a comeback
• 1 June 2026 – Williams is awarded wildcard for Queen’s, partnering Victoria Mboko in the women’s doubles
• 9 June 2026 – Williams wins on doubles return but has to pull out of the tournament two days later after Mboko suffers an injury
• 16 June 2026 – Williams continues her comeback at the Berlin Open, partnering Karolina Muchova, and receives a wildcard for the women’s doubles at Wimbledon, partnering sister Venus
• 21 June 2026 - Williams receives wildcard for women’s singles at Wimbledon

Image source, Getty Images

After 1,462 days away, Serena Williams is BACK at Wimbledon.

The 44-year-old is due on Centre Court at 19:26 BST, where she'll face Australian Maya Joint in her first singles match since the 2022 US Open.

Williams, who received a wildcard into both the singles and women’s doubles, hasn’t won a match at Wimbledon since 2019, when she lost to Simona Halep in the final, with first-round exits in 2021 and 2022.

The American tuned up for Wimbledon with doubles matches at Queen’s and the Berlin Open.

Tim Henman
Former British number one on BBC Two

First and foremost, Alexander Zverev will be delighted with the win. As the scoreline suggests, it was not easy, but when you break down the way he was able to hit the spots with his serve and get his first serve percentage so high, it gave him a very strong platform.

It is an impressive win, but I'm pretty sure we are going to be seeing a lot more of Alexander Blockx. He did himself proud.

Simon Reed
Commentator on BBC Two

Alexander Zverev is on his way, hoping to be back-to-back champion in Paris and here at Wimbledon, but he was pushed all the way by 21-year-old Alexander Blockx.

For the most part, he showed majestic serving.

Next on Centre Court, it's the return of Serena Williams.

Plenty of build-up to come before her first-round match against Maya Joint, plus reaction from Alexander Zverev following his progression into round two.

Alexander Zverev has bossed this tie-break, winning the first five points without reply.

Tim Henman
Former British number one on BBC Two

Alexander Blockx showed a lot more quality in the second set tie-break compared to the third set tie-break in which he made a lot more mistakes.

He has already given the advantage to Alexander Zverev, who will be keen to back things up with a couple of big serves.

Image source, Getty Images

A rueful look from Alexander Blockx after he plants a return into the net to go 3-0 down in the fourth-set tie-break.

We're into a third tie-break of the match.

If Alexander Zverev wins it, he'll be into the second round.

If Alexander Blockx wins it, it'll go to a deciding set.

Image source, Getty Images

Stan Wawrinka and Matteo Berrettini look destined for another tie-break on court one.

They're tied at 4-4 in the second set and neither player has offered up a break point.

Alexander Zverev responds with a hold to love of his own, that wobble on serve earlier in the set seemingly behind him now.