After falling flat on his back and firing long, Ben Shelton fires down an ace and then another unreturnable serve to stay within touching distance of Jannik Sinner.

Not quite as straightforward as Ben Shelton made his last service game look, but that's a fairly comfortable hold for Jannik Sinner, who doesn't have to do anything special to get it over the line.

Annabel Croft
Former British number one on BBC Radio 5 Sports Extra

Even with that last point there - Sinner was not hitting with the same authority, not the same depth or sound out of the racquet and he's taking a lot of time inbetween. He's slowed up and looks a bit hot, like he's not feeling so well.

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Jannik Sinner won't get much time to recover. That was short and sweet from Ben Shelton, who gets his first love hold of the match.

Back to you, Jannik.

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

That was a key game for Sinner for sure.

A bit of a chance to maybe recover and rest in this game because he's still sitting strongly on the scoreboard.

Jannik Sinner isn't rolling over. Ben Shelton gets his racquet to the serve but he can't do anything with it.

And the second seed won't offer up any further chances as he gets the hold over the line.

Third time lucky? Jannik Sinner flings the ball into the net and gifts Ben Shelton another break point.

Nope. We head back to deuce as Ben Shelton overcooks a forehand.

Ben Shelton worked so hard to get bring up that break point but it all goes to waste as he plants what should be a simple strike into the net.

But he'll get another look. Can he get this one?

What a point! And what a chance for Ben Shelton.

The American comes out on top of a 20-shot rally, gradually making his way to the net before striking the decisive blow with a fierce forehand winner.

Patient play from Jannik Sinner as he defends from the baseline and waits for Ben Shelton to make the first mistake. And that's exactly what happens, with the American finding the fence.

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Ben Shelton is known for his big serve, but it doesn't seem to be troubling Jannik Sinner too much as the Italian works his way to a 0-30 lead.

Shelton squashes the immediate danger, getting to deuce, but then he goes wide and hands Sinner a break point opportunity.

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

Shelton looks a bit more relaxed on that backhand now - allowing that talent and ease and power to take over.

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Jannik Sinner doesn't give Ben Shelton another sniff, wrapping up the hold to get on the board in this second set.

Lovely stuff from Ben Shelton. Jannik Sinner stops in his tracks and thinks the American's lob is going long, but it lands perfectly just inside the baseline.

And then, after being 40-15 down, he works his way to deuce with a huge backhand winner down the line.

After finding himself 0-15 down, Ben Shelton ups the ante and rallies back with some big serving and he manages to get out of trouble.

Advantage, Jannik Sinner. That's one part of the job done for the Italian.

He wraps up the opener with a blistering ace after landing a superb cross-court winner. Ben Shelton stood no chance there.

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Annabel Croft
Former British number one on BBC Radio 5 Sports Extra

There's so much to admire in the way Sinner's striking the ball.

So pure, struck with such authority and linear and low over the net. Like someone launching a spear into the corners and landing in craters at every corner of the court. He's outmaneuvering Shelton every time.

No mercy from Jannik Sinner.

He defends at the baseline before plotting his attack with a move to the net, and he slams down a winner that Ben Shelton has no chance of getting to.

Shelton gets his revenge when he almost takes the Italian out with a brutal first serve which forces Sinner to duck.

The eighth seed apologises, but Sinner waves it away and takes the loss. He's got the chance to serve out the opener now.

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Jannik Sinner has found his rhythm and he's on a roll.

Four back-to-back winners and he grabs a love hold, making it all look incredibly effortless.

The pressure is back on Ben Shelton to hold serve and stay in this opening set.