Annabel Croft
Former British number one on BBC Radio 5

"Ernests Gulbis has proved today what a talent he is. He has bossed a lot of the points and he does have this huge serve which has won him a lot of points. Roger is certainly not in control of this match."

Abigail Johnson:, external WHAT back injury??? Absolute fake from Gulbis to throw Roger.

Stewart Mills:, external Gulbis must be wearing his magnetic underpants today... Every one of Federer's easy put-always is going straight to him.

Roger Federer is snarling. Battling back from 0-30, he batters down an ace to give himself set point and celebrates with a pointed look down the other end at Ernests Gulbis.

The Swiss is in the ear of the umpire on the next point, complaining as his forehand is belatedly, but correctly, called long.

Finally he has the set bagged up to help sooth that fraying temper and we are into a fifth.

A whistlestop hold from Ernests Gulbis and Roger Federer will serve for the fourth set for the second time next time.

Roger Federer's turn to set his stare to stun. The Swiss is shooting daggers down the opposite end of the court as Ernests Gulbis emerges from his time out like a man reborn, hitting a series of clean winners to break to 15.

There's magic in that physio's sponge.

Federer still a break up though.

Milos Raonic has the edge on Marcel Granollers already on Court Suzanne Lenglen, breaking for an early lead.

Ernests Gulbis is not the sort of man you would send in to solve a hostage situation.

Suddenly the wheels are coming off quite spectacularly on court and off court.

His shots are erratic and he is bubbling like Vesuvius.

After gifting Federer a second break, and in all probability the fourth set, he strides off court to get treatment in an area that is not suitable for public airing.

Federer is left alone on court and will have to make sure that he carries his momentum across to the other side of the delay.

Piers Newbery
BBC Sport at Roland Garros

"If the tournament organisers were worried they were missing a pantomime villain after Fabio Fognini's defeat yesterday, Gulbis has helpfully stepped up to the plate. Federer is nearly as popular as Jonny Wilkinson in these parts and chants of "Roger, Roger" ring around the stadium as their man moves ahead in the fourth set.

"Gulbis plays his part by staring down someone in the court side VIP seats, drawing a few boos. He loves it really."

Image source, Getty Images

'Jeu Federer', says the umpire while Ernests Gulbis stares into the middle distance, ticking like a time-bomb.

He is riled after Federer converts a break point with a marginal call on the baseline. The umpire hops out of the chair to confirm that Gulbis has pushed long.

Court Philippe Chatrier don't care for the underdog. Federer is their man and the cat-calls descend as a fuming Gulbis heads back to his stool.

Over on Court Suzanne Lenglen, Milos Raonic will be hoping to make it an all-round excellent day for Canadian tennis by joining Eugenie Bouchard in the last eight.

The world number nine is coming off the back of his best clay-court season ever, the highlight being a semi-final appearance in Rome.

He has held serve in the opening game against Spain's Marcel Granollers.

The last time that Roger Federer missed out on the French Open quarter-finals was 2004.

Ernests Gulbis has been in pretty hot form this season - with only Rafael Nadal (37), Federer (31) and Tomas Berdych (31) racking up more than his 30 tour wins this season.

He has also won his last four meetings with seeded opponents in Grand Slams.

On serve in the fourth.

Image source, AFP

Default Girl on Twitter: , external"Federer just looks human today."

Roger Federer stalks down a backstage corridor to take a toilet break. It might be time for an Andy Murray-style word to himself in the mirror.

Right now, he is being bested by Ernests Gulbis. The third set is flushed away via another break of the Swiss's serve.

Are Leo and Lenny to blame? Or is it Father Time putting a kindly hand on his shoulder?

Image source, Getty Images

Roger looks rattled, dumping himself into his seat with a 5-2 third-set deficit after the longest rally of the match- 27 shots.

Rattled in a different way is Carla Suarez Navarro, who fumes at the crowd she is belting balls into to celebrate a 6-3 6-3 win over Ajla Tomljanovic. If she's that fearsome when she wins, what's she like when she loses?

Piers Newbery
BBC Sport at Roland Garros

Andy Murray has just been talking to the media, not surprisingly a touch wearily, but he is hopeful of being fit and ready to face Fernando Verdasco on Monday. The Scot explained the physical issue he struggled with against Philipp Kohlschreiber, saying: "I was cramping. That was what it was. It wasn't something I went into the match with. It was the first five set match I played since my surgery. It was obviously playing late, heavy conditions, so it is tough on the legs in the evening."

Ooohhhh, is that the sound of an upset developing, of a story breaking? King Roger of Switzerland dumps a backhand into the net to give Ernests Gulbis a break in the third set.

Carla Suarez Navarro made the quarter-finals on her Roland Garros debut back in 2008. Her long wait for a return to the last eight is almost at an end.

The Spaniard is a break up and a set to the good against Ajla Tomljanovic.

We are shouting out your favourite hairstyles from tennis's history.

Lee Mabey:, external "Best hairdo is early Murray - the afro really was a sight to behold."

Image source, Getty Images

Dominic Inglot
British doubles player on BBC Radio 5

"I'm surprised by Roger Federer. His backhand isn't going to hurt Ernests Gulbis. If he uses the slice more I think it would be more beneficial for him.

"Instead, he has been drawn into this tug of war of who can hit the ball bigger."

Ernests Gulbis has a very presentable record against Roger Federer. The 25-year-old has beaten Federer once in their three meetings and taken a set off the Swiss in his two defeats.

He has at least a set to take from this latest encounter. The Latvian prevails 7-3 in the second-set tie-break.