But Federer holds to level with a smash. Forehand error from Wawrinka. His serve...

Here we go. Federer sticks a backhand volley into the tape after a long rally.

Tie-break time! Gather breath for about 30 seconds.

Federer plays a remarkable drop shot at 15-15 as Wawrinka slides towards the ball, sticking out his hand to gather because he can't get his racquet anywhere near. That gives Federer the momentum and he sees the game out with a neat volley.

The Roland Garros crowd are loving this Swiss spectacle - and rightly so. The tension mounts. A long rally ends in Wawrinka edging 30-15 ahead. Wawrinka screams in delight, Federer screams an expletive. Pardon his French....

But that uncharacteristic release of anger is maybe what Federer needed. He responds with a forehand which Wawrinka can barely touch and gives him half a chance of a break.

Then Federer sees a backhand ping off the racquet and off the court, before making back-to-back unforced errors as Wawrinka moves within one game of the match. Again...

Image source, AFP

Wawrinka's serve has been excellent - but so too has Federer's. The Swiss number two has rarely pushed his illustrious rival when he is tossing the ball and this game is no different. Easy hold for Federer. However, he is still on the ropes....

Did anyone think Wawrinka would run out of steam? Er, it may have been said. But not so. The 2014 Australian Open champion shows no mercy against his nemesis - forcing Federer into mistake after mistake to win the ninth game of the third set. And that means he is one game away from the match....

Is this a chance for Wawrinka? Federer gifts the first point to his opponent, but roars back with a meaty return and a booming ace that Wawrinka can only stand and watch whizz past. A forehand winner puts Stan back in with a shout, only for him to see Federer claw his way to a much-needed hold.

Simon Cambers
Tennis journalist on BBC Sport online commentary

"Wawrinka has got everything he needs to win another Grand Slam. He's become a player who rises to the big occasion."

Image source, Getty Images

Neither man looks like throwing away their serve at the moment. Wawrinka relentlessly peppers the Federer territory with big serves, throwing in some heavy returns, to force his opponent into mistakes with his replies. Job done for Wawrinka. Over to you Roger....

What impact a change of shirt has on Federer I'm not too sure. But it does him no harm in the sixth game, Federer easing to the game with a near-perfect service game which ends when Wawrinka hammers an unconvincing return long.

Wawrinka looks to be fading ever so slightly - unsurprising after the high-energy, all action performance so far. But he has enough energy to see out his serve pretty comfortably.

Wawrinka has the ice-cool Federer sweating - and it is only partly due to the Paris heat. The world number two strips off his lilac shirt - to a chorus of wolf whistles - for a fresh number.

I hope nobody with seats on Suzanne Lenglen has nipped to the Roland Garros toilet - they will have missed a flurry of games. The games are flying by quickly, with both Swiss men holding serve as the opening four are equally shared after just 13 minutes.

Federer responds with a hold of his own - but it wasn't straightforward. Wawrinka gets to deuce - forcing Federer into another internal panic - before the 17-time Slam winner restores calm to hold.

These two are not messing about on Suzanne Lenglen - a quick breather and they are back to their feet. While our eyes were cast over Tsonga clinching the second set, Wawrinka had already wrapped up the first game of the third set with a hold.

Image source, Reuters

Don't worry about the noise levels on Court Philippe Chatrier - the decibel meter has just combusted. The Parisian crowd are going wild as their man Jo-Wilfried Tsonga moves closer to the last four at Roland Garros for the second time.

Piers Newbery watching Nishikori v Tsonga
BBC Sport at Roland Garros

"It's hardly convincing but Tsonga earns a two-set lead over Nishikori at the second attempt.

"The Frenchman led 6-1 5-2 when play was halted and promptly dropped serve on the resumption, then played a very nervy service game at his second chance to win the set. A big serve at 30-30 settled the nerves, and a running forehand does the job."

Simon Cambers
Tennis journalist on BBC Sport online commentary

"Federer is not getting angry, but instead he looks resigned to his fate. He's not imposing his game on Wawrinka."

Roger Federer could do with showing some of the fight famously shown by his missus towards Wawrinka at the ATP Tour final., external Plus an ice cold bucket to douse Wawrinka - the man is on fire!

Wawrinka spanks a beauty of a cross-court backhand past Federer to nick another break point and then completes the job at the first attempt.

Wawrinka whoops in delight - and that's about the only noise inside Suzanne Lenglen. Everyone else is shellshocked....

Simon Cambers
Tennis journalist on BBC Sport online commentary

"Wawrinka is bullying Federer at the moment. Unless Federer can push him back he's not going to turn this around."