All eyes on Court Suzanne-Lenglen now then.

Good timing. We're right at the business end of this set.

At 30-30, Djokovic just clips the line with the backhand. A couple of millimetres make all the difference, had that gone wide he'd have been in danger.

Instead, the defending champion wins the next point to force Thiem to take us into a tie-break.

Excellent work Dominic Thiem.

Both set points saved and then he takes the game with the next two points.

He's got more ATP Tour level wins this season than anyone this year, bar Rafa Nadal. You can see how.

Poor Pablo. You can't help but feel sorry for Carreno Busta. He can hardly serve. Not how he saw his first Grand Slam quarter-final panning out.

An easy break of serve for Rafa.

Back to normality. Back to the grind.

Thiem wins a 23-shot rally with a winner but he's still in danger, now facing 15-30.

How many times have we seen this from Djokovic over the years? One minute he looks distracted, the next he's like another Jaws movie, a shark hunting the kill.

Thiem goes wide. Two sets points to Djokovic...

Carreno Busta does not look in great shape. The Spanish 20th seed is not really stretching for the more testing Rafa Nadal baseline returns, gently patting a couple long and a couple into the net.

He might be weighing up in his mind whether it is worth carrying on and doing himself more damage, or calling it a day and protecting his body ahead of the grass-court season.

Image source, Reuters

Piers Newbery
BBC Sport at Roland Garros

The media and public seats alike are a lot busier on Lenglen, where the rain is starting to fall very gently. It looks like it might pass overhead without delaying us. It will only make conditions here even heavier and slower for the players though, something that is not likely to brighten Djokovic's mood.

Now Djokovic seals a game without any trouble.

The first part of this set was all heavy hitting and energy sapping running but now we've hit a little lull.

A couple of Djokovic's support team have their hoods up. Hopefully to keep their ears warm rather than to keep themselves dry. We don't want any more rain.

Impressive from Thiem.

After a few lengthy games in a row, the Austrian holds comfortably.

Pressure back on Djokovic. He looked close to wrapping up this set. Now he's serving at 4-4.

Here he is. Carreno Busta returns to a huge cheer from the Chatrier crowd. Possibly because he is topless.

He sticks on his Borg-style tee, jogs to the receiver's ends and waits.

Rafa to kick off the second set...

Still no sign of Carreno Busta. The umpire talks hurriedly into his walkie-talkie, presuming being told from inside the Chatrier corridors what is going on.

Rafa goes through some side-to-side running drills. Like the sort you do in football training. Then he decides to crack down a few serves...

Djoko sends his racquet bouncing into the red clay and that tells you all you need to know.

Thiem breaks back.

A very slack game from Djokovic. Not often we say that.

Image source, Reuters

Thiem has been the far greater risk-taker in this match, hitting 10 winners but 14 unforced errors. Will he change up his tactics now he's fallen behind?

Maybe he won't need to. Back-to-back double faults from Djokovic are followed by a backhand error. Uncharacteristic stuff from the world number two.

Two break back points to Thiem.

While Nadal pops off to the gents at the changeover, Carreno Busta looks to be in a bit of bother. Is it a stomach problem? He's holding his midriff before calling a medical timeout and lying down on a mat for some treatment.

The Spaniard disappears back into the locker room, while Rafa - throwing on a tracky top - jogs on the spot next to his chair to keep warm.

Image source, Getty Images

Piers Newbery
BBC Sport at Roland Garros

The loudest noise so far on Chatrier has been the squeaking of the flag poles in the wind, until the collective gasp as Nadal dropped serve.

Uncle Toni looks on from the stands, arms folded and cap pulled firmly down as always - every match now is potentially the last time we will see him in the Chatrier player box, as he will be stepping away from life on the tour at the end of 2017 to run his nephew's academy in Majorca. A retirement well earned.

A set down on Chatrier, we're not half way through the opener here on Lenglen.

After missing the chance to break in the last game, Thiem now hits three unforced errors in the opening four points of this one. Not ideal. 15-40.

There's another. Djokovic gets his nose in front.

Cheap. Pablo Carreno Busta gifts the set to Rafa Nadal as he fails to hold his serve.

And it is not just any old handover. Nadal hasn't beaten him by brilliance. Carreno Busta has beaten himself.

A double fault brings up the break point... and then he does the same again! The 20th seed shakes his head. Restrained. I'd have taken it out on my racquet.

Image source, EPA

Is this game finally over? Nope.

"Out," shouts the line judge after a Thiem backhand but the umpire disagrees. It clipped the line. Replay the point.

This time world number two Djokovic does the job. Phew. I'm tired just watching this.

We've not seen many sloppy games from Rafa Nadal at Roland Garros this year. But here's one.

The Spanish fourth seed hands the game on a plate to his compatriot, four unforced errors - two off his forehand and two off his backhand - give Carreno Busta some hope in this opening set.

There have been five break points so far in this match - and all five have been taken.

Image source, Getty Images

Ten minutes this Djokovic service game has now lasted. The work both players have put into it is enough to put off us mortals from picking up a racquet.

Thiem finds the line with a another powerful forehand and Djokovic can't deal with it. Still we go on. 12 minutes and counting...