Tsitsipas continues to find his target with the accuracy of a top-of-the-range sat nav, landing more first serves - including another ace - to move 40-0 ahead.

Are we ever going to see a receiving point won? Yes. Thiem cracks a forehand winner for 40-15 then gets back to 40-30.

But the Austrian is rocked back on the baseline by a Tsitsipas return which he can only bat back long.

Anything you can do Stefanos...

Thiem kickstarts his side of the scoreboard with a similarly easy opening hold to love. Tsitsipas doesn't do enough on the Austrian's second serves, batting a forehand long to seal the game for Thiem.

Image source, Getty Images

You know you've gone big when you get to meet the Prime Minister. Just ask Noel Gallagher.

Greek's top political dog Kyriakos Mitsotakis, looking very casual in his civvies, took time off from the mountain of work on his desk yesterday to watch his country's leading star.

Not sure if Mr Mitsotakis is one of those waving his Greek flag tonight...

Andrew Castle
BBC Sport tennis commentator at the O2 Arena

Well, that's a nerve settler isn't it!

Matthew Henry
BBC Sport at the O2 Arena

Nerves in the biggest final of your life? No sign of it from Stefanos Tsitsipas.

Going off my early estimates there are more Greek flags in the stands than Austrian.

What. A. Start! Never mind the chalky tablets, this is what settles the stomach of a tennis star. An easy hold to love for Tsitsipas, finished with a pair of aces which leave Thiem wafting at this air-conditioned air.

Image source, Reuters

Right then, here we go. Popcorn at the ready.

Stefanos Tsitsipas to serve first...

Flashback Sunday...

Tim Henman
Former British number one on BBC Two

We've been building up this next generation of players and they have been knocking on the door but it seems they have proved it this week. These two players have been phenomenal and have beaten the very best. Now they have the chance to win the biggest title of their careers.

Those face masks should be in the 50p bargain bin today.

Matthew Henry
BBC Sport at the O2 Arena

Just £1 for a player face mask from one of the shops at the O2.

Sadly it seems they haven’t been quick enough to print any Thiem or Tsitsipas ones yet. It’s Djokovic, Nadal and Federer only.

Image source, BBC Sport

While Tsitsipas was chilling in a swanky Docklands hotel last night, Thiem and Alexander Zverev were slugging it out for the right to face him today.

Thiem didn't reach the full throttle of his explosive wins against Roger Federer and Novak Djokovic, perhaps partly because he was still a little under the weather with a cold, but took advantage of Zverev choking on the big points to win 7-5 6-3.

"This is a big, big dream coming true for me," Thiem said afterwards.

Image source, EPA

Stefanos Tsitsipas was the first man to book his spot in today's finals after keeping his hero Roger Federer at bay in their semi-final.

The swashbuckling Greek fought off 11 of 12 break points created by the Swiss, taking three of his own four, to win 6-3 6-4 and reach the showpiece match on his ATP Finals debut.

"I grew up watching Roger here at the ATP Finals and Wimbledon and other finals. I wished one day I could face him and today I'm here living the dream," Tsitsipas said afterwards.

"I remember myself being one of the kids here watching the event and I could never picture myself here. But it can happen.

"Dreams can come true!"

Matthew Henry
BBC Sport at the O2 Arena

The O2 certainly knows how to build an atmosphere. Deafening music, followed by silence, then the lights go out and a thumping heartbeat is played over the sound system.

The players then emerge to a huge roar.

This should be good.

Image source, BBC Sport

Tsitsipas looks longingly down the camera like a weepy singer shooting his latest music video as he waits in the bowels of the O2.

Thiem, after a few stretches with a resistance band, joins him shortly after before we hear that familiar heartbeat...

DUH-DUH. DUH-DUH. Showtime...

Matthew Henry
BBC Sport at the O2 Arena

And then there were two.

Stefanos Tsitsipas and Dominic Thiem may not be the finalists many predicted but I reckon they’ve been the best two players across the full week.

Hello! A new king of the ATP Tour will be crowned at the O2 tonight.

Will we celebrating the coronation of Stefanos the Great?

Or the anointing of Dominic the Brave?

All the pomp of the ceremony is about to begin...

Not sure if Stefanos Tsitsipas and/or Dominic Thiem have a 90s R'n'B playlist on their Spotify accounts, but if they have then they will certainly know this classic.

And yesterday, following their respective semi-final successes, both men were a soulful croon away from sounding like they were doing a karaoke version of Gabrielle.

"Dreams come true!" gushed Tsitsipas after he beat Roger Federer to reach the final on his debut at the O2.

And after Thiem beat Zverev, he came out with almost the same line... "This is a big, big dream coming true for me."

One of them will realise another dream tonight - winning the biggest trophy of his career.

Image source, Getty Images

Dreams can come trueLook at me, babe, I'm with youYou know you gotta have hopeYou know you gotta be strooooong