Jonathan Jurejko
BBC Sport senior tennis reporter at Flushing Meadows

At the end of the first set, President Trump was booed much louder than earlier when he appeared on the jumbotron.

The camera lingered for much longer than it usually does on famous faces, too.

The reception from the New Yorkers was markedly different when rock icon Bruce Springsteen - a local hero from New Jersey - appeared to euphoric cheers.

Trump sat stony-faced as Springsteen, who has been a vocal critic of the president, grinned.

Marion Bartoli
Former Wimbledon champion on BBC Radio 5 Live

The stadium is starting to really come alive as people are finally able to get into their seats. We are in for an amazing final.

Sinner has come into play and is finally getting his returns in on the Alcaraz serves. He was missing so many in the first set.

Sinner gets it.

This is more of what we expected. An unusually slow start from Sinner but he takes control of the second set.

Game on.

Here we go.

Sinner has arrived. The Italian executes a drop shot and is waiting to volley a winner across the opposite side when Alcaraz returns for 0-30.

The world number one appeals to the crowd to get behind him and they do.

He has three break points.

Marion Bartoli
Former Wimbledon champion on BBC Radio 5 Live

Image source, Getty Images

Alcaraz is showing his first to his opponent on every point he wins. He wants to make sure everyone is aware that he is not going anywhere.

He is using the slice because Sinner has a tendency to slow down the pace on the slice ball. Alcaraz is looking to get that ball that sits up slightly more.

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

Image source, Getty Images

Alcaraz is like a conductor displaying all of his amazing skills. He knows exactly what he is doing in constructing the points.

Sinner is ramping things up and Alcaraz will be able to feel that.

Maybe a first sign of some of that Sinner grit we know so well. The Italian comes through a gruelling 15-shot rally to level at 15-15.

Sinners opens up his chest and fizzes a winner into the corner for 40-15 before turning away and pumping his fist in celebration.

And there's the hold. Much better from the world number one.

Jonathan Jurejko
BBC Sport senior tennis reporter at Flushing Meadows

There have been more uncharacteristic errors from Sinner than we're used to seeing.

You can't help but wonder if that stomach issue he had in the semi-finals is worse than he let on.

Or maybe that elbow injury which flared up at Wimbledon has resurfaced. He continues to wear a compression sleeve on his serving arm.

One for the post-match news conference...

Alcaraz continues to dominate on serve.

A swift hold to love settles him down into the second set.

Sinner just can't get a read on him at the moment.

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

Alcaraz deserved a break point in that game. He looks very clear in his head tactically, there is no hesitation whatsoever.

Sinner is retying his shoes to perhaps get some more grip on the surface.

Marion Bartoli
Former Wimbledon champion on BBC Radio 5 Live

Image source, Getty Images

There is lots more coming forward from Alcaraz than we have seen in his matches against Sinner. He is also going towards Sinner's forehand a lot more.

When Alcaraz plays like this with so few errors, he is unplayable.

Saved.

Sinner hangs on for now at deuce.

A big serve is returned wide by Alcaraz and the Spaniard puts into the net on the net point.

A crucial hold for Sinner - he had led 30-0 before losing three points to hand over that break point.

Hmmm.

Still some creases to iron out.

A double fault brings Alcaraz to 30-30 and then Sinner puts into the net.

Hands up, who was expected such a one-sided opening set?

Not me.

Sinner is on serve to begin the second set, let's see if he can make a positive start.

Jonathan Jurejko
BBC Sport senior tennis reporter at Flushing Meadows

Carlos Alcaraz's serve let him down in the Wimbledon final.

Not today. Well, not so far, anyway.

The Spanish second seed drops just THREE points on serve to win the first set.

Once Alcaraz snaffled the break, there was no way he was letting it out of his grasp.

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

Sinner hit a shot there right at Alcaraz's body - you do not see that very often. Perhaps he was trying to get rid of some adrenaline in his body.

A jaw-dropping level from Alcaraz. We saw a little bit of everything from him - mixing up the paces, serve and volley.

Image source, Getty Images

Well, that was impressive.

Brilliant serving - Alcaraz lost just three points on his own serve in that set - coupled with that fizzing forehand and a brilliant variety of shots and the Spaniard is in control.

Sinner has some answers to find.

A bit of a smirk on the face of Sinner as Alcaraz makes another reaction return at the net and pulls it off.

The Spaniard has three set points.

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

Another service game where Sinner looked under pressure.

It will be interesting to see when Sinner starts looking towards his camp. He normally keeps his emotions in but when he looks across there, you will know he is starting to feel uncomfortable.

Alcaraz is in the driving seat.

Image source, Getty Images

Alcaraz serving for the set after 34 minutes. Sinner is going to have to find some answers in the second set.

As we know with this match-up, anything can happen.