Nick Kyrgios gets the break he needs and is now serving for the third set and a 2-1 lead.

He sprints back to his chair, and can't help himself but mock a fan who had taunted him over a previous serve.

"Great return. Good return," says Kyrgios to the fan in the stands.

Gauff takes the opening game of the second with a brilliantly measured backhand winner.

The American turns away and allows herself a little fist pump.

Gauff then comes out on top in a couple of rallies and finds herself with two break points.

They both go begging, however, and Ruse survives another scare.

Gauff has converted just one of her 10 break points in this match.

Nick Kyrgios has two break points. He'll be serving for the third set if he takes one of them, 15-40.

Jana Fett can't make a cross-court forehand, instead burrying the ball into the net for deuce, and Iga Swiatek slams a huge first serve out wide to wrap up the hold.

One more like that and she'll have the first set under her belt.

Harry Poole
BBC Sport at Wimbledon

More harsh words from Nick Kyrgios in the direction of the line judges directly behind him, suggesting some might need their eyesight testing.

Tense moments now at the business end of the third set. The next few minutes could have a huge say in determining the outcome of this one...

Paul Jubb is 0-30 down on his serve. "Let's go," shouts out Kyrgios, pushing for what would be a massive break of serve in the 11th game of the third set.

It is very quiet on Centre Court.

The crowd wake up, though, as a short Swiatek forehand finds the net for deuce.

It's already been a good day for Great Britain in the men's singles as Ryan Peniston gained his first ever win at a Grand Slam.

Watch below as he hit a "stunning volley" on his way to beating Henri Laaksonen 6-4 6-3 6-2 at Wimbledon.

Ouch.

Jana Fett double faults and the double break goes to Iga Swiatek.

That's a great hold from Paul Jubb and the world number 219 is showing his class today against an opponent who is 40th in the world and been as high as 13th.

If Jubb can break Kyrgios' serve in this game then he will take the third set.

Iga Swiatek is the best front-runner in tennis at the minute.

Her shots are so big, so full of power, and it draws the errors out of Jana Fett, who overhits in response.

A wild forehand brings up another two break points for Swiatek.

Some great reactions from both men, volleying the ball at close range with both at the net. The crowd love it, with Kyrgios getting the winning shot, on his way to deuce.

It's a comfortable hold to love from the Romanian and she takes the opening set!

Gauff does not look comfortable at all, but there's still time for a comeback.

That's better from Swiatek and a first serve is sent out of bounds by Fett to hand the Pole her third game in a row.

All credit to Paul Jubb, he's not been bothered by Nick Kyrgios' antics and is just focusing on his play in the biggest match of his career.

We're still on serve in the third set and this is a big set in determining who will go into round two.

That was a chance for Jana Fett but she's too uppish on a forehand, and it drifts long for deuce.

Hello.

An error from Swiatek and it's break back point to Fett...

Gauff is really struggling with her forehand and the American's troubles present Ruse with another break point, which she takes!

The favourite is really up against it here as Ruse prepares to serve for the opening set.

Sonia Oxley
BBC Sport at Wimbledon

You cannot overstate just how hard Swiatek hits that forehand - there are audible gasps during points from fans, who are presumably glad they are at a safe distance away from the action on this show court rather than at very close quarters on an outside court.

Iga Swiatek finds herself in a touch of trouble at 15-30 down before she smacks a huge forehand into the corner of the court, and Jana Fett nets.