We're already seeing some lengthy rallies between the pair - 17 shots, the last one was - as Daniil Medvedev brings the score to 30-30.

Jannik Sinner fires down the first ace of the match before Medvedev goes long with a forehand as the Italian top seed holds.

Lulu Sun did bring up a first break point but Donna Vekic quickly dismissed it before bring up a game point of her own with a lovely drop shot.

That in turn is stopped by Sun but Vekic goes again.

An ace takes her to advantage and another big serve allows her to advance and hammer a forehand winner top clinch the hold.

Still on serve in his first set but both players have had break opportunities now.

Emily Salley
BBC Sport at Wimbledon

Daniil Medvedev is up to his usual antics early doors and he gets a loud chuckle from the crowd after asking to challenge the very first point.

He get's that one wrong. "Daniil Medvedev has two challenges remaining," says the umpire.

Two strong first serves does the job at deuce and Daniil Medvedev holds.

Joe Rindl
BBC Sport at Wimbledon

A huge roar after Lulu Sun sets up break point.

Sun is definitely getting more love from those on Court One. Holding twice despite seeing 11 deuces on your serve will almost always get the crowd to warm to you.

The 23-year-old hasn't really acknowledge the support back to be fair. Her style seems to be head down and focus on the play.

Daniil Medvedev interestingly challenges an out call on the first point of the match, which is upheld, before double faulting, providing Jannik Sinner with a 0-30 lead.

The Russian gets himself out of trouble, however, winning a couple of rallies, as the game goes to deuce.

Image source, Getty Images

That's more like the Lulu Sun we saw against Emma Raducanu on Sunday.

The qualifier gets around and opens up her body to drill a forehand winner into the corner. No chance for Donna Vekic.

Vekic does get it to deuce again but this time that is the only one as Sun goes on to hold.

Emily Salley
BBC Sport at Wimbledon

Anyone up for a repeat of the Australian Open final?

Daniil Medvedev looked like he was closing in on his second Grand Slam title before Jannik Sinner launched an epic comeback from two sets down in Melbourne.

That lasted almost four hours, so we could be in for another long one today.

Here they both come to open Tuesday's proceedings on Centre Court.

Here come Jannik Sinner and Daniil Medvedev to a warm reception on Centre Court.

I've already spotted some familiar faces in the crowd, including Michael McIntyre, Stephen Fry and Sir Steven Redgrave.

Italian top seed Sinner wins the toss and chooses to receive first.

No such messing about in this game, Donna Vekic holds to 15 with a minimum of fuss.

The Croatian has been the more dominant on serve so far.

Martina Navratilova
Nine-time Wimbledon singles champion on BBC TV

Image source, PA Media

Sun has better variety than Vekic, moves better and serve is maybe even.

She is absorbing the pace pretty well and defending beautifully. Still though, that was a long service game which is exhausting mentally and physically.

Donna Vekic goes and has a look at a spot on the court after completely missing the ball for a routine forehand.

It clearly didn't bounce as she expected and a third break point goes begging.

There won't be a fourth in this game. Lulu Sun gets to advantage and finally ends an epic hold early in this match with an ace down the T.

Joe Rindl
BBC Sport at Wimbledon

We're locked in on Court One. Lulu Sun's current service game is on to its 10th deuce. The qualifier has saved four break points.

The crowd are loving this already.

Donna Vekic brings up a second break point and the longest rally of the match by far ensues.

Vekic seems to be in control of it but Lulu Sun hangs in and eventually the Croatian finds the net with an attempted drop shot.

Back-and-forth they go. Sun gets to advantage for the seventh time but still she can't convert. Ninth deuce coming up.

Getting us under way on Centre Court shortly is the mouth watering quarter-final between Italian top seed Jannik Sinner and Russian fifth seed Daniil Medvedev.

The pair come into the match on the back of relatively straightforward fourth round victories, with Sinner beating American Ben Shelton in straight sets and Medvedev's Bulgarian opponent Grigor Dimitrov retiring injured in the first set.

The contest is a repeat of January's Australian Open final, where world number one Sinner came back from two sets down to beat Medvedev.

A win for either athlete will see them equal their best run at Wimbledon, with Sinner and Medvedev both losing at the semi-final stage last year.

Image source, Getty Images

Joe Rindl
BBC Sport at Wimbledon

The crowd on Court One are cheering that little bit louder for Lulu Sun, but that's not to say Donna Vekic isn't getting any love.

There's been a lot of talk about Sun, and why not, she's a qualifier in the last eight and is hoping to become the first New Zealander to reach the semi-finals in singles at a Grand Slam for 35 years.

But Vekic also has an intriguing journey.

The 28-year-old Croatian is further than she's ever been at Wimbledon and is hoping to reach a semi-final at a major for the first time at the third attempt.

In 2019 she lost to that year's champion Belinda Bencic in the last eight of the US Open. At last year's Australian Open she was beaten by winner Aryna Sabalenka in the quarters.

Under a smidgen of pressure at 15-30, Lulu Sun hits a big forehand out wide and advances to put away a thumping volley.

Donna Vekic still manages to bring up the first break point of the match but nets a backhand.

Sun thrice gets to advantage without managing to close it out, a double fault frustrating her on the second occasion, before a crisp forehand down the line gets her there again.

But this time she sends a forehand into the net. Fifth deuce and on we go...

Centre Court is starting to fill up now as fans escape the rain to await the arrival of Jannik Sinner and Daniil Medvedev.

Their quarter-final tie will be followed by the last-eight contest between Jasmine Paolini and Emma Navarro.

Image source, BBC Sport

Easy as you like for Donna Vekic as she holds to love.

A lovely cross-court forehand winner is the highlight of the game for the Croatian.

Comfortable hold to 15 for Lulu Sun.

No signs of nerves early on in her first Grand Slam quarter-final.

*denotes next server