Pat Cash
Former Wimbledon champion on BBC Radio 5 Live

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Nuno Borges has been playing really well.

He is serving at 77% first serves. Don't get me wrong, they aren't the hardest serves in the world but they are big and he is hitting the ball cleanly.

This is a very even match - and it isn't surprising that we are in a tie-breaker.

Too good from Aryna Sabalenka, who slams a return over which McCartney Kessler can do little about.

The world number one reacts with a bellowing "come on".

Kessler reacts superbly, getting to game point but can't get over the line as a forehand spoons wide.

129mph ace from Nuno Borges - lovely.

Jannik Sinner immediately surrenders his advantage with a loose backhand but keeps his nose in front with an inside-out forehand.

Jannik Sinner offers a clenched fist of celebration - a rare show of emotion - as he lands a backhand pass for an early mini-break.

Not a great decision to follow a mis-hit into the net from Nuno Borges, the ball sitting up nicely for Sinner.

Aryna Sabalenka puts too much into a powerful forehand which sails long, drawing oohs from the crowd.

McCartney Kessler's backhand winner then sends the game to deuce.

Sabalenka reacts well by winning an entertaining rally before a strong first serve seals the hold.

Jannik Sinner trails 0-15 but it's the briefest of scares. He rattles through the next four points to hold.

Harry Poole
BBC Sport at Wimbledon

Sadly we saw the end of Dan Evans' playing career after his earlier defeat alongside Henry Searle, but we have plenty more British players in doubles action today - quite the treat for those without tickets to the main show courts.

I've nipped over to court eight, where three of the four players in action are competing at their home Grand Slam.

Ten years after his run from qualifying to a second-round meeting with the great Roger Federer on Centre Court, Marcus Willis, playing alongside David Stevenson, is up against Joe Salisbury, a six-time major winner in doubles competitions, and Uruguayan Ariel Behar.

This is another well-attended match, with viewing space at a premium, and the crowd which has gathered here do at least have the comfort of knowing at least one British player will be celebrating at the end.

The first set goes the way of Salisbury and Behar.

Oh, that's quite lovely from Nuno Borges. Coming on the approach, he winds up with a flat racquet face before switching angle at the last second to ping a cross-court forehand winner. Cool as you like. Jannik Sinner was completely wrong-footed.

For a second time, Sinner will have to serve to stay in the set, but having only dropped two points all match, a tie-break feels inevitable.

Chris Bradnam
BBC Sport commentator at Wimbledon

You are really now starting to hear from Kessler.

The crowd wanted a match after the quality of the first set and they are getting one.

With help of her brother, you can see the tactical switches. It is a real turnaround now from Kessler.

It is getting better and better.

Tom Corrie
Tennis expert on BBC Radio 5 Live

Aryna Sabalenka had the highest performance rating, which takes into account basically everything that happens in a match, in round one of the women's singles with 9.44. It was basically near-perfect tennis from her.

That metric isn't to do with winning or losing, it is to do with everything you're doing in a match such as how you are moving or hitting the ball.

She has actually come out the blocks today and topped it with a 9.49 rating. Her score has dropped a little bit in this second set, though.

Aryna Sabalenka keeps herself in the game with a perfect backhand winner down the line.

McCartney Kessler responds by going toe to toe with Sabalenka in a rally, before seeing out the hold with a strong first serve.

She's potentially one game away from sending this match to a deciding third set.

Nuno Borges rocks back his head in frustration as he nets a forehand off a quite pedestrian second serve. It was well-placed by Jannik Sinner, however, cramping him for room. 40-0.

We stay on serve.

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Emily Salley
BBC Sport at Wimbledon

Well that woke anyone up who wasn't paying attention. Jannik Sinner blasts a blistering forehand into the umpire's chair and it makes an almighty thud.

The umpire seems a bit shocked too, and there's a chuckle when he finally remembers to read out the score.

Oh my! Jannik Sinner, dragged off court by Nuno Borges' wide serve, slams a forehand into the base of the umpire's chair with a booming thunk. Sharp reactions from the ball kid to duck out of its way.

Borges breezes through a hold to love.

Amy Lofthouse
BBC Sport at Wimbledon

Sabalenka and the entire Court One crowd just gave Kessler an ovation for that point at the net. Stunning.

What a point as Aryna Sabalenka puts absolutely everything into a cross court backhand, which somehow McCartney Kessler reacts to in time to volley it over at the net.

Sabalenka responds with a forehand winner of her own, before shouting "come on".

You can't take your eyes of this match at the moment as a return winner from Sabalenka sends the game to deuce.

Jannik Sinner's radar goes awry at 40-0 as he puts a down-the-line backhand into the tramlines.

No matter. He comes on the approach off his next serve and drives home a forehand winner. One-two punch.

Marion Bartoli
Former Wimbledon champion on BBC Two

The beauty of tennis, it is not only about deserving but converting.

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Now then. A rare chance in this match for McCartney Kessler as a long Aryna Sabalenka forehand offers two break points.

The pair get locked in a short rally and it's Kessler who triumphs as Sabalenka skews a backhand wide.

Kessler has the break!