I tell you what is great to see... both players wearing headbands. Headbands should be mandatory on the tour. Super-cool.

Thiem wallops another sizzling of a forehand down the line, not for the first time, for 15-30.

Can he press home the advantage? Nadal tries to slow him down, whacking the base of his shoes with his racquet, slowly looking up to give the Austrian a glare.

It doesn't work. A baseline rally ends when Nadal goes long with a forehand. Two more break points to Thiem...

Image source, Reuters

But the problem is that when you don't land these heavy hits then you can be caught slightly out of position. And that's what happens.

Rafa beautifully controls a cross-court forehand to set up advantage, then an unforced error from the Austrian sixth seed hands over the fourth break point of the game.

Rafa dug himself out of a hole in that previous game, now it is Thiem's turn to need a spade.

The Austrian faces three break points.

Who needs a spade when you've got a racquet? Thiem has got some serious power with his forehand - he's out-Rafaing Rafa!

Three absolute hammers - all around the 100mph mark or just short - beat Rafa all ends up on his forehand side.

Image source, EPA

Kristine Kirby: What. A. Fighter. Rafa was going to hold his serve if he had to stay out til dark and past Theim's bedtime. 2-1, on serve.

Nadal survives. Thiem can't convert either of those points and Rafa goes on to hold in deuce.

Some very loud warning signs for Rafa though.

These two know each other's clay-court games inside out, especially as they have seen each other more than their partners in recent weeks.

Barcelona, Madrid, Rome, now Roland Garros.

Two more breakpoints for Thiem...

Image source, Reuters

Is that our first 'Vamos!' of the match? I think it is.

Rafa roars in the direction of his box after breaking straight back. Two unforced errors from Thiem level things up.

Christopher David: This match has a Sampras/Federer Wimbledon 01 feel about it. Master vs the apprentice

Image source, Getty Images

What. A. Start!

Well, for the young Austrian at least. The sixth seed, helped by some Nadal sloppiness that we haven't seen over the past fortnight, snaffles a break point in the very first game.

Two big questions here: who is going to win this match? And how long is it going to go on for?

I can't answer the first yet. But, I reckon, a rather-vague answer to the second is that it could deep into the Parisian evening.

Especially judging by the opening four points. A quality forehand winner gets Nadal up and running, but a double fault gifts Thiem half a chance at 30-30...

Caught your breath back after that Murray match? Stocked up on the supplies? Excellent.

We go again.

Nadal to start us off...

So is Rafa back to his best?

"It's starting to be the way it was," Carlos Moya, who joined Nadal's coaching team in December, tells BBC Sport.

"That was one of the things that we wanted back, that the opponent feels he's playing Nadal again and if they want to beat him, they're going to have to work really hard."

Enough to send a shiver down the spine of an opponent.

Image source, Getty Images

Over the last couple of years, many doubted whether we would Rafael Nadal at the business end of a Grand Slam again.

But now, with an imperious run in Paris, he is two wins from La Decima - a record 10th win at Roland Garros.

He is the favourite. Opponents so far have been dispatched without the slightest concern.

The Spaniard has reached the semi-finals for the loss of just 22 games in five matches - the fewest games lost to this stage of a Grand Slam since best-of-five matches were introduced.

He has not won here since 2014 but that was the last of nine French Open wins in 10 years.

Chatrier is barely a quarter full, but the players are almost ready. Nine-time champion Nadal and Thiem, looking to reach his first Grand Slam final, pose for a couple of cheesy photographs at the net before knocking up.

Image source, Getty Images

Blimey! The Roland Garros organisers aren't messing about. Rafa Nadal and Dominic Thiem are already out on Chatrier.

We thought there would be a longer delay as they clear out those ticket holders who watched the Murray v Wawrinka semi-final and get the next lot in.

We were wrong...

Britain's Andy Murray after his five-set semi-final defeat by Stan Wawrinka: "I'm proud of the tournament I had, I did well considering. I was one tie-break away from getting to the final and when I came here I was really struggling so I have to be proud of that.

"Maybe the lack of matches got me in the end because it was a high intensity and when you have not played loads, four or four-and-a-half hours can catch up with you.

"But I turned my form around really well and had a good tournament all things considered."

Andy Murray has popped almost straight down to the media room, speaking to the assembled journalists before presumably heading to Charles de Gaulle airport as soon as possible.

The world number one says he is "proud" of his performance at Roland Garros. And rightly so. Full quotes on the way.

Paul Christie: When do we start seriously questioning Murray's underachivement in Grand Slams? For a player of his talent 3 is a poor return

Thoughts?

Pat Cash
Former Wimbledon champion on BBC Radio's online-only commentary

Image source, EPA

It was a good performance in the end. To be through to the semi-final and in it until the last set is a terrific performance.

He didn't serve as well as he would have wanted and didn't hit enough winners or push Stan around.

Typically that has been an issue in his whole career but that is the way he plays.

It was a very good fortnight for him. Andy will be upset and will have things to work on but I think in a few days he will reflect and say that was pretty good.