Coco Gauff has another opportunity to take control of this opening set after Solana Sierra's forehand strays long.

After losing her previous service game, Coco Gauff goes back to basics and it pays off.

A comfortable hold to 15 keeps this opening set on serve.

Ace. Double fault. Nuno Borges breaks right back. That was unexpected.

That's a poor leave from Jannik Sinner. He pulled out of his backhand volley but Nuno Borges' shot landed comfortably inside the baseline. 0-15.

With a loose forehand, the Italian is down 0-30.

A double fault. 15-40.

A messy start to the third set from both players.

Solana Sierra gets the hold after Coco Gauff gets her angles wrong and sends a forehand wide of the paint.

Great resilience shown from Sierra to come through that game after trailing 30-0.

Emily Salley
BBC Sport at Wimbledon

Ah. It felt like Nuno Borges really had a chance of springing a shock result on Centre Court, but it feels like any momentum that he once had is gone.

The Portuguese player is looking more and more frustrated in between points and he gives his bag an angry smack when he returns to his chair.

John McEnroe
Three-time Wimbledon singles champion on BBC One

This could be curtains here losing this point. This set could get away in a hurry.

Borges should have won that game, now he is in huge trouble. If it wasn't bad enough at two sets, to get broken in the first game.

If the [negative thoughts] weren't there before they will be now humming in his brain.

Coco Gauff's backhand is causing some major problems for Solana Sierra. The American makes a positive start to lead 30-0 against the serve, but Sierra starts to target the forehand and gets enough joy to win three successive points.

Gauff refuses to let the game completely get away from here and gets to deuce.

Image source, PA Media

Jannik Sinner has broken in the opening game of the third set!

He rifles his forehand at the advancing Nuno Borges, who can only parry the ball into the net.

Borges smacks his racquet bag at the change of ends.

Nuno Borges is inviting this pressure on himself. Another error.

Jannik Sinner fails to return a first serve back into the court.

Eek. Another error from Nuno Borges, putting a backhand into the net.

And in the blink of an eye it's back on serve on Court One.

Solana Sierra gets the job done at the third attempt. That'll do her the world of good.

Jannik Sinner liked that one! Sprinting across the baseline, he wraps his racquet around the ball and drives it beyond an outstretched Nuno Borges at the net. 15-30.

He's less impressed with his forehand two points later, firing it well beyond the baseline, but lets out a small "come on" as Borges gifts deuce.

Actually hold that thought.

Solana Sierra has other plans. The Argentine looked nervy in the opening couple of games but digs in and earns three break-back points.

Coco Gauff has an early break!

The American could not have asked for a better start. Gauff might be keen to get this wrapped up quickly so she can watch England play DR Congo at 17:00 BST.

Image source, PA Media

Russian eighth seed Daniil Medvedev has fought back to take the second set 6-3 against Spain's Daniel Merida.

Medvedev is a two-time semi-finalist at Wimbledon while Merida is playing in his first ever second-round match at a Grand Slam.

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

That is a bit of killer blow for Borges losing the second set.

He had done a great job controlling the game from the mid-court.

He played a very good set, but couldn't hold his serve. His speed dropped on his forehand. He blinked, gave Sinner that opportunity and now he has a mountain to climb.

After watching top seed Aryna Sabalenka battle to a straight set win earlier on Court One, Coco Gauff will be eager to do the same.

The American makes a positive start with a routine hold to 15.