It's one-way traffic at the moment as Coco Gauff goes 0-40 up on Taylor Townsend's serve.

Townsend manages to save two but then goes long to hand over another break.

Gauff is firmly on course for round two.

Coco Gauff races to a 3-0 lead in the second set.

She has dropped just one point on serve in her first two service games of this set. Taylor Townsend needs to start making some inroads into it if she is to avoid a straight-set defeat.

Coco Gauff wins her opening service game of the second set to love and then comes up with a couple of brilliant passing shots on Taylor Townsend's serve.

Townsend then shovels the ball wide on an approach shot to allow Gauff a break point.

And a double fault from Townsend means the defending champion is a set and a break up.

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Daniel Kiernan
Former British tennis player on BBC Radio 5 Sports Extra

I think nerves have hit Siegemund at the wrong time but the match-up of this is fascinating because I think Osaka likes that flat, fast ball that plays into her strengths where Siegemund will give you everything but that.

It will be interesting how this unfolds now.

Laura Siegemund had set point but she wastes it with an audacious drop shot attempt that fails to clear the net.

That's all the encouragement Naomi Osaka needs to win the next two points and break back.

Having wasted a set point on her own serve, Coco Gauff finally clinches the first set with her second opportunity on Taylor Townsend's serve.

The fourth seed pumps her fist towards her box - the defending champion has her first set on the board but it took almost an hour of hard toil.

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Naomi Osaka might have impressed with her fashion, but right now things aren't so golden for the former world number one.

Laura Siegmund has broken the 16th seed's serve and will now try to serve for a deciding set.

She doesn't get off to the best start, though. Double fault.

A moment for Naomi Osaka's outfit...

The four-time Grand Slam champion arrived on Court Suzanne Lenglen in dramatic fashion, wearing a black gown that was layered over a gold tennis dress.

Sparkles, sequins, the lot.

Image source, Getty Images

Image source, Getty Images

Coco Gauff looked to be back in control in the first set but Taylor Townsend has other ideas.

First Gauff has to save three break points, and then when she does find herself at set point, she double-faults.

Another double fault gives Townsend another breaking opportunity, and the American left-hander yells "Come on!" as she breaks with a sweeping backhand cross-court winner.

We're back on serve!

Russell Fuller
BBC tennis correspondent on BBC Radio 5 Live

What Norrie said to me in Rome is that before his first match, he couldn't feel in a better place in terms of confidence or the way his body was feeling.

By his own admission, he went early to Geneva and probably over-trained and he didn’t listen to his body and his mind.

It’s frustrating because the players have so much data available to them but it's in Norrie’s DNA - he just can't really leave it alone and that's what's made him the player he is today. He loves being out there.

"COME ON!"

Naomi Osaka lets out a mammoth roar after saving two break points to stop Laura Siegemund from opening up a 4-2 lead.

The Japanese 16th seed had let her level drop, but only briefly and a couple of cross-court forehand winners get her back on track.

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Coco Gauff is starting to work her way into this match now while Taylor Townsend's level has dropped a bit.

Gauff earns a couple of break points and will now be serving for the first set.

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Fourth seed Coco Gauff dropped her opening service game on Court Philippe-Chatrier - not the ideal start to the defence of the crown she won last year.

However, she then broke fellow American Taylor Townsend in the sixth game to get things back on serve and has just held serve to move ahead in the match for the first time.

But Townsend, who is known more as a doubles specialist, is giving Gauff plenty to think about.

On Suzanne-Lenglen, Naomi Osaka has won the first set of her match against Germany's Laura Siegemund.

The Japanese 16th seed needed just the one break of serve midway through the set to secure it.

Annabel Croft
Former British number one on BBC Radio 5 Live

I think Norrie has done the right thing if he is in pain. It's far better not to exacerbate the injury problem and get back to the UK, have rest and treatment on it, and then start building up to Queen's Club and Wimbledon.

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Cameron Norrie attempts a couple of serves but he is clearly struggling with his ribs and his breathing.

Such a disappointment for the British number one, who has never previously retired during a Grand Slam match.

Adolfo Daniel Vallejo of Paraguay has won on his Grand Slam debut.

Annabel Croft
Former British number one on BBC Radio 5 Live

When you're coping with some kind of injury like this, you're sort of sussing it out every time you move or hit the ball, you're assessing it all the time and I think losing the first set would have been so huge in his head - knowing he's got to fight his way through it.

Cameron Norrie is carrying on - for now at least - but can't make any inroads into Adolfo Daniel Vallejo's serve.

The Briton is really up against it now.

Cameron Norrie is not looking happy and has another chat with his team at the change of ends.

Now the doctor comes out and it looks like the rib injury that has prevented him from practising is once again impeding him.

Cameron Norrie went over to his coaching team in the break between sets and there was some intense discussion along with some shoulder-shrugging from Norrie.

It doesn't appear to have any positive impact, as Norrie throws in two double faults, one of which concedes the game.

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