Oh that's very good from Mertens. She draws Raducanu into the net then comes in herself and sends one behind the Brit into the corner.

None of these service games have been particularly easy for Raducanu. She's having to grind them out but she looks pretty confident in doing that. Deuce.

After that win over eighth seed Casper Ruud, Italian Fabio Fognini then gave the crowd an entertaining and honest post-match interview.

Jonathan Jurejko
BBC Sport at Wimbledon

Romeo Beckham is a footballer these days, playing for Brentford's ressies.

A bona fide pro is tightly marking him in the stands.

Sami Khedira, the former Real Madrid, Juventus and Germany midfield maestro, is parked in the seat right behind young Becks.

More episodes of Celebwatch later...

This time she gets it!

A brilliant forehand pass to the back corner of the court after Mertens had come into the net.

Raducanu just seems so up for this.

Eighth seed Casper Ruud is out of the men's singles after a 6-4 7-5 6-7 (1-7) 6-3 defeat by Fabio Fognini.

The Norwegian fought back from 5-2 down in the third set but had no answer to the Italian in the fourth.

This could not be going any better for Raducanu.

She has another couple of break points on the Mertens serve.

Mertens saves the first, sending Raducanu one way then wrongfoots her and sends her forehand behind the Brit.

Alan Jewell
BBC Sport at Wimbledon

A satisfying 'thwack' under the Centre Court roof as Naomi Osaka opens with an ace against 19th seed Emma Navarro. It's a solid hold to 15 to start for the four-time Grand Slam champion.

Image source, Getty Images

Daniil Medvedev was talking after reaching the third round: "It was a very tough physical match. Alex played well. Some moments in the match was very tough to stay in touch with him. I managed to stay solid. Next time I will try to do better."

What happened at the end of the tie-break?

"At the end of the first set my thoughts were not good. I went to sit in my seat and the referee was saying 6-3, 6-3 and I didn't even hear him.

"I tried to stay composed, and I turned the match around."

He often gets court one, but is Centre Court where it is at? "Centre Court for some reason feels much slower. I need to get used to it. The more I play on it the more chances I have to get used to it.

"I am always happy to play in Centre Court if I win."

Image source, Getty Images

Five years on from her last appearance at Wimbledon, Naomi Osaka made a winning return as she beat world number 53 Diane Parry 6-1 1-6 6-4 in round one.

The Japanese former world number one, 26, is a four-time Grand Slam champion but has never been able to show that sort of form at the All England Club.

In fact, Osaka has never made it to the second week and would match her previous best at SW19 with a win today.

That is far from guaranteed, though, with 19th seed Emma Navarro standing in her way.

Navarro was dominant in dispatching Wang Qiang 6-0 6-2 in less than 50 minutes in the first round.

It was the 23-year-old American's first Wimbledon win as she continues a breakout year that seen her move into the top 20 of the WTA rankings.

Image source, Getty Images

Bit of a trickier hold but Raducanu seals that one as Mertens can only send her forehand wide.

So far so good for the Briton.

Jonathan Jurejko
BBC Sport at Wimbledon

We've got a Beckham in the house.

No, not David. He was here on Monday.

Victoria? Nope. Brooklyn? Forget it... it's Romeo.

Beckham Junior II, once a promising tennis player who hit with Andy Murray at Queen's in 2016, is here supporting Emma Raducanu.

Laura Robson
Former British number one on BBC Radio 5 Live and BBC Sounds

One thing we can look at as the match goes on is that Elise Mertens can throw in some double faults when she is under pressure on the second serve.

That's when she starts to get frustrated. The racket can be thrown at times and she can have a bit of a chat with her player box.

If you can get under her skin, she does let it show.

Jonathan Jurejko
BBC Sport at Wimbledon

Sharp intakes of breathe. Air sucked through teeth. Whoops of delight.

All the feels for the Raducanu fans inside Court One so far.

Charlotte Coates
BBC Sport at Wimbledon

Dan Evans’ Wimbledon journey is over at the first hurdle.

It’s a real shame for the Brit after he fought so hard to recover from a knee injury.

You can see the heavy strapping on his leg as he prepares to leave court 12.

Image source, BBC Sport

Half of the seats inside court one are still empty. I imagine there's plenty of people waiting in the wings to get to their seats at the change of ends.

Perhaps some of you are here following along with me? Well you've missed a Raducanu break but you might have had chance to grab a Pimm's so swings and roundabouts.

Laura Robson
Former British number one on BBC Radio 5 Live and BBC Sounds

This will be very tough [for Emma Raducanu].

Elise Mertens has been around for a very long time now, very experienced player and consistent in her singles career.

She knows what she is doing. She is going to have to use all of her experience today. She will have a very clear game plan.

Ahh. Raducanu slams into the net twice as Mertens saves break points to take us to deuce.

Mertens goes long and that brings up another opportunity for Raducanu and this time she takes it with a perfectly timed drop shot.

Raducanu brings up two break points. The Brit looks confident with the backing of the crowd.

Don't forget we're live on BBC One with this match or you can hit the 'watch and listen' at the top of this page to pick your match.