Image source, PA Media

Great serve from Jannik Sinner, when he truly needed it as well. He sends Zverev wide and the German hooks his cross-court forehand wide.

Marion Bartoli
Former Wimbledon champion on BBC Radio 5 Live

If you look at the body language from Sinner, the fist pumping is slightly longer towards his camp. You can sense and feel from the ball toss of Zverev on the first point that he is feeling the tension more now.

Into the net from Jannik Sinner, and suddenly Alexander Zverev is back involved in this tie-break.

Jonathan Jurejko
BBC Sport tennis news reporter at Wimbledon

Everything feels very different now on Centre Court.

Zverev has started this tie-break nervy, while Sinner looks in complete control.

The Italians around us - and there are plenty - are getting increasingly loud.

They had to pipe down though when they realised that lob was long.

Out by a fraction! Jannik Sinner, on the stretch, is millimetres from a fifth straight point there. The Italian sees the funny side and smiles towards his team.

Alexander Zverev nets from the back of the court!

Jannik Sinner is on a roll here and Zverev can't handle him.

The dream start for the world number one.

The pressure is on, but he is rising to the occasion.

Jannik Sinner lands a forehand into the back of the court for a three-point advantage.

A good return from Alexander Zverev, but Jannik Sinner takes charge of the point and moves two points ahead as Zverev misses the baseline.

With Alexander Zverev playing the way he is, this is absolutely massive for Jannik Sinner.

He's off to the perfect start after Zverev misses - and the Italian roars in celebration.

Image source, Getty Images

That's wide from Alexander Zverev - and we are off to another tie-break!

Tim Henman
Former British number one on BBC One

You feel that Sinner is under so much pressure, he hasn’t done much wrong. Now he has to hold serve here and then win such an important tie-break.

Gigi Salmon
BBC Sport tennis commentator on BBC Radio 5 Live

If Jannik Sinner doesn't win this set and then has to win three more sets, we have to put the stat out that he has never won a match that has lasted more than three hours and 48 minutes. He is zero to eight when it has hit that mark.

Stunner! Alexander Zverev passes Jannik Sinner with a forehand down the line to take the opening point on the world number one's serve.

Zverev is then millimetres away from landing a shot on the baseline. Wow, that's a huge relief for Sinner - who is also grateful to see Zverev fail to return a drop shot for 30-15.

Image source, Getty Images

Another whopping serve from Alexander Zverev. He isn't giving Jannik Sinner a hope of getting anything meaningful on these first serves.

Zverev knocks a forehand into the tramlines, but a couple of excellent serves complete the job once more.

The second seed guarantees himself at least a tie-break, but can now have a real crack at the Sinner serve in search of a two-set lead.

Jannik Sinner shakes his fist in the direction of his team after blasting in an ace to safely capture another service game. Still no way through for either player.

Marion Bartoli
Former Wimbledon champion on BBC Radio 5 Live

This feels like going back to the old days of Wimbledon, with the likes of Goran Ivanisevic and Pete Sampras serving three or four aces a game.

Zverev's serving has been incredible.

Jonathan Jurejko
BBC Sport tennis news reporter at Wimbledon

As often is the case, things start getting a little out of hand by 6pm on a scorching Sunday - especially if the Pimms takes hold.

One chap is getting particularly vocal as he shouts in support of Sinner.

Umpire Eva Asderaki-Moore scolds him in the manner of a school teacher.

"Sir, that's enough now," she warns.

Final strike...

Jannik Sinner beats Alexander Zverev with a brilliant sliced drop shot for 30-0, but misses a cross-court forehand after recovering one of the German's drop shots on the following point.

Sinner relieves some tension after holding his nerve in an exchange for game points, but nets a routine volley for 40-30.

The pressure builds.

Tim Henman
Former British number one on BBC One

There are slim pickings for Sinner on these serves.

Image source, Getty Images

A massive game here for Jannik Sinner.

If he plays it like any of his other service games so far today, he will be fine. But that is not how the mind works, not on this stage with so much on the line.