Jannik Sinner is grimacing in between points and it looks like he wants this whole thing over and done with as quickly as possible.

The Italian top seed is attacking Ben Shelton's serve and he brings up three break points with a brilliant passing winner with a backhand volley.

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Jannik Sinner might be dealing with some injury issues but he's not letting it impact his tennis.

Two huge forehand winners and then a massive backhand down the line see him through a love hold.

Jannik Sinner called for the trainer during the changeover and he's had some treatment on his right thigh, plus a bottle of pickle juice!

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Ouch. Ben Shelton has been threatening on Jannik Sinner's serve, but it's him who is broken first in this third set.

The American is not happy and he shows his frustration by flinging his racquet off the floor.

Yikes. A double fault from Ben Shelton and it's another break point for Jannik Sinner.

Jannik Sinner is limping. He leapt hard into that backhand and he seems to have come out the worse for wear as he sees it fly well beyond the baseline.

It doesn't stop him on the next point though as he takes control from the baseline and stays patient until Ben Shelton goes long. Deuce.

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Jannik Sinner misses the first break point, but just as soon as it's gone he's got himself another.

But Ben Shelton isn't giving up and he slams a forehand winner down the line to bring us back to deuce.

A double fault is followed by two misses from Ben Shelton and now it's Jannik Sinner's chance to break and take a lead in this third set.

Mark Woodforde
17-time Grand Slam doubles champion on BBC Radio 5 Sports Extra and BBC Sounds

Jannik Sinner is just taking some time in-between points to walk off any possible cramp.

It's probably just a bit of self-awareness to keep walking and not let that tension build-up.

We have seen Shelton take a very short amount of time between fast points, but Jannik is taking plenty of time at the moment.

Jannik Sinner stays cool, calm and collected with an ace before Ben Shelton skews a backhand into the sky and long.

More missed opportunities for the American and it seems like this match is heading in only one direction now.

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Jannik Sinner saves the first break point with a sublime forehand winner down the line and Ben Shelton can't do anything on the return from the defending champion's 121mph serve.

Another miss from Jannik Sinner and Ben Shelton, all of a sudden, has two break points.

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Mark Woodforde
17-time Grand Slam doubles champion on BBC Radio 5 Sports Extra and BBC Sounds

Jannik Sinner is going to be gassed after those last two points.

It has come alive again with the quality from both players. Ben Shelton, that is some point!

I know it sounds crazy, but you should have more of a value than just one point for something like that - it should be two points!

That is fantastic from Ben Shelton as he does brilliantly to stay in the rally and force a forehand winner down the line despite being pushed out wide by Jannik Sinner.

The crowd are getting behind Shelton now and he seems to be thriving off that.

Sinner then opens up a half-chance for Shelton as he finds the fence. 0-30.

"YEAAAAAAH!"

Ben Shelton has been relatively quiet during this match, but he lets out a huge roar there as he blasts a forehand winner down the line.

A fiery backhand nearly takes the racquet out of Jannik Sinner's hands and the following cross-court drop shot from Shelton leaves the defending champion with absolutely no chance.

There's another shout from Shelton as his ace seals the hold. He needed that.

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From a deft volley to an overhit backhand and then a wild forehand that flings wide. Ben Shelton just can't string a couple of points together and it helps Jannik Sinner secure the hold.

Nicely done from Ben Shelton, who takes charge of the rally before making his way to the net and lifting over a brilliant backhand volley. Deuce again.

Ben Shelton's biggest problem today has been not converting his break point chances.

And there's another one that's gone missing. Back to deuce.

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Ben Shelton had done so well to rattle off a couple of returns at the net, but Jannik Sinner stays in the point and eventually Ben Shelton can't keep up.

But the American has got himself a break point as Sinner fires wide.

A clenched fist from Ben Shelton as he overcomes a mid-game double fault to grab the hold and avoid an early break once more.