Here's one to look out for when watching BBC coverage.

The HawkEye graphics have been upgraded. They now have blades of grass flying about when the ball hits the court...

Image source, BBC Sport

You can definitely see Carlos Alcaraz is a little bit nervous, his feet haven't settled yet.

Mark Lajal doesn't know what losing is during the last week so he has to just keep going.

Lajal's backhand is very, very good.

Two break points for Mark Lajal, 15-40 in game five.

Well look at that. Charles Broom is turning the tide.

Stan Wawrinka hit an unforced error into the net and the British wildcard has a chance here after gaining a break of serve at the start of the second set.

Image source, PA Media

I think the family set up for Carlos Alcaraz gives him a very stable existence. He's got a very good work ethic, very good values and understanding of what he has to do.

All of those pieces of the puzzle have come together at such a young age and that's what makes it very exciting thinking about the next five, 10, perhaps even 15 years for Alcaraz.

Mark Lajal looks to have a fine serve on him, with one effort at 131 mph proving too fierce for Carlos Alcaraz. A hold to love against the reigning champion on Centre Court. The 269th in the world is proving a handful.

What a point! It's 'ooh after 'ooh' from the crowd until Carlos Alcaraz ends the rally by smashing down Mark Lajal's audacious lob attempt.

Charles Broom hasn't been totally swept aside in this first set but nevertheless he loses it in less than 25 minutes.

Broom has been punchy and fought well, but Wawrinka's cool and composed play has left the Brit very few chances.

The only real moment of note was Broom forcing deuce on Wawrinka's serve in the opening game of the match.

That will make Mark Lajal feel relaxed as he holds his first service game against reigning champion Carlos Alcaraz. The Estonian looks like he's enjoying every second of the biggest occasion of his career and is quickly on the board.

Former finalist Matteo Berrettini won a first-set tie-break against Marton Fucsovics of Hungary on court 12.

Frances Tiafoe, the 29th seed, was two sets down but is on the brink of taking his match with Matteo Arnaldi to a decider.

In the women's draw, French Open runner-up and seventh seed Jasmine Paolini has just got under way against world number 55 Sara Sorribes Tormo.

Image source, PA Media

Daniil Medvedev takes the first set - but not without a momentary scare.

He finds the net to give Aleksandar Kovacevic three break-back points before a good second serve then two big first serves get the fifth seed out of trouble.

Kovacevic then sends a backhand into the net and, in a flash, from 0-40 down, Medvedev holds to go a set up.

What an opportunity this is for Mark Lajal.

He had never won a Grand Slam qualifying match before last week. Now he's on Centre Court playing the defending Wimbledon champion.

The Estonian is rocking his trademark blond dreadlocks which are sticking up at all angles out of a ponytail.

Regarded as one of the sport's great entertainers, Gael Monfils is back at Wimbledon after two years away for what could be his last appearance.

A wrist injury kept the 37-year-old out of last year's tournament and his world ranking plummeted to 394. He considered retiring before being talked out of it by his team and wife Elina Svitolina, the former world number three and a semi-finalist at SW19 last year.

Monfils is now the oldest male player in the sport's top 90 and last year he became the fourth-oldest to win an ATP title since 1990 with his victory at the Stockholm Open.

Known for his athleticism and stunning shot-making, Monfils won the boys' singles title at Wimbledon in 2004 and has been as far as the last 16 in the men's event.

We're at 4-4 in the opening set on court 18 in his match with fellow Frenchman Adrian Mannarino, the 22nd seed.

Plenty of famous faces in the royal box watching defending champion Carlos Alcaraz on Centre Court - including Sir David Attenborough, David Beckham, Katherine Jenkins and Alexander Armstrong...

Image source, PA Media

Image source, Reuters

Image source, Reuters

Mark Lajal takes the opening two points of the match off the Alcaraz serve, but doesn't get the perfect start of a break in the first game as Alcaraz, aided by an ace that kisses the line, recovers and holds his serve.

Stan Wawrinka has pulled ahead of British wildcard Charles Broom.

Broom didn't win a point in the last service game, hitting a number of unforced errors.

He now has much to do in this first set.

A huge cheer from the crowd as defending champion Carlos Alcaraz and Mark Lajal make their way onto Centre Court.

There's a real buzz and 'vamos Alcaraz' chants are being belted out as the players start their warm-ups.

Estonia's Mark Lajal, 21, is in the main stages of a Grand Slam for the first time in his career after he gained qualifying wins last week over Italy's Francesco Passaro, Portugal's Henrique Rocha and Australia's James Duckworth.

It is a no-lose situation for Lajal and what an experience as he got the dream draw - reigning champion Carlos Alcaraz on Centre Court day one. What a chance for Lajal to make a name for himself.

Alcaraz to serve first.

• Casper Ruud, Grigor Dimitrov and Maria Sakkari among the first-round winners on day one
• Great Britain's Heather Watson loses in straight sets to Greet Minnen - six more British players scheduled to be in action on Monday
• World number three Aryna Sabalenka pulls out of Wimbledon because of a shoulder injury

Still to come: Emma Raducanu, Coco Gauff, Jannik Sinner and plenty more...

Big cheers from those in attendance on Court One as Aleksandar Kovacevic - having let Daniil Medvedev back into with a couple of unforced errors at 40-15 - holds to get on the board.

There are a few chuckles midway through the next game after an early contender for the worst challenge of the tournament.

I'm not sure if Kovacevic thought the Medvedev serve was wide or long but it was neither - HawkEye showed it was in by at least six inches, probably more, in both directions.

After all that, Medvedev holds to 30 for the third time in the set.