Image source, Getty Images

Jannik Sinner is trying to hype himself up, shaking his fist as Nuno Borges puts a backhand into the net.

He gets on top of a cross-court forehand exchange and celebrates more as Borges nets again. 0-30.

Borges levels the game at 30-all, with Sinner guilty of giving up a golden opportunity for break points with a limp backhand after hunting down a drop shot, and the world number 48 completes the recovery with a couple of hefty first serves.

Aryna Sabalenka had to be at her best at times to overcome McCartney Kessler there, who performed admirably on Court One.

Sabalenka's win sets up a third-round tie with former French Open winner Jelena Ostapenko.

Relief for Jannik Sinner as he finally completes a routine hold in the second set. Ace, forehand winner, ace, serve and volley.

But how is he going to manufacture a breakthrough on Nuno Borges' serve?

American 16th seed Learner Tien was struggling with some sort of injury or illness in the fourth set of his second-round defeat with Hungary's Marton Fucsovics.

He was not moving very well at all, was delivered some food (what looked like some dry bread) by one of the ball kids during one of the changeovers and then had a medical timeout in which he received some treatment.

Amy Lofthouse
BBC Sport at Wimbledon

It may have took a bit longer than she’d have liked but that was impressive from Sabalenka, first to hang it when Kessler was playing some glorious tennis and then to brush off those missed match points on her serve.

Jeff Tarango
Former American tennis player on BBC Radio 5 Live

McCartney Kessler can be happy with how she adapted after getting trampled on in that first set. She played a great match but Aryna Sabalenka somehow managed to pull it together.

Jannik Sinner, hunting down a drop shot, pulls the trigger on a cross-court forehand but is denied by the net cord. 30-0.

Nuno Borges holds to 15. He's not giving Sinner a sniff on serve in this second set.

There could be an upset in the making on court two with Spain's Daniel Merida taking the first set against eighth seed Daniil Medvedev.

Merida broke Medvedev to lead 4-2 and held his nerve to see out the set.

The world number 84 can count himself lucky to be in the second round too. He was a set down against Camilo Ugo Carabelli in his previous match before the Argentinean retired due to injury.

Emily Salley
BBC Sport at Wimbledon

Image source, Getty Images

Jannik Sinner hasn't been playing badly, but he needs to be careful - Nuno Borges is playing out of his skin so far on Centre Court.

And as I said earlier, the crowd love an underdog. The majority seem to be on Sinner's side at the moment, but they'll want to get their money's worth and see as much tennis as possible. A straight-set win isn't much fun for anyone but the winner!

Aryna Sabalenka brings up another match point, on serve this time, but she can't take it as another shot finds the net.

Remarkable.

Jannik Sinner underhits a forehand drop shot and the ball rolls down the net with a whimper. He's looking quite flat. 30-all.

He escapes another iffy service game with an ace down the T and a big serve out wide.

A change of shirt for the Italian.

It's brilliant from Aryna Sabalenka as she keeps her cool to drop a volley over near the net following a back and forth.

Which way is this one going?

Image source, Getty Images

Jeff Tarango
Former American tennis player on BBC Radio 5 Live

McCartney Kessler has been so competitive in this set. As she learned in college tennis: 'Never give up' because you never know what is going to happen out there.

She was down match point but she acted like it was the first point of the match.

McCartney Kessler saves match point as Aryna Sabalenka can't stretch enough to return a backhand.

The American then brings up a set point of her own.

Nuno Borges piles on the pressure with a quickfire hold to love, aided by a couple of unforced errors from Jannik Sinner, who gives the base of his back/right hip a rub in between games.

Aryna Sabalenka slaps her thigh in frustration as a backhand finds the net.

Moments later the Belarusian somehow drops a backhand over the net when it looked like McCartney Kessler was about to earn two set points.

This is gripping stuff.

Jannik Sinner saves the first break point with an ace but gifts Nuno Borges the lead on the second.

Borges had done well to keep Sinner pegged back off a second serve, targeting his backhand. The Italian resorts to running around one but fires his forehand disgustingly long.

Image source, Getty Images

McCartney Kessler isn't going anywhere. The American fights back before edging ahead with a big first serve.

Aryna Sabalenka responds by getting the better of a rally and the pair go into the change of ends level at 3-3.

Now then. Another sticky service game for Jannik Sinner, including a double fault and a poor netted forehand, and suddenly he's facing two break points early in the second set.