When asked about his unbeaten semi-final record at Wimbledon, Federer replied: "I don't want to get too far ahead of myself, I am just glad I am back strong after the disappointment of last year. I left really deflated last year so it's great to be back in the semi-finals and having the chance to go one or two steps further."

Roger Federer speaking to BBC Sport after beating Stan Wawrinka 3-6 7-6 6-4 6-4: "It's always nice playing on Centre Court or even in England for that matter, I always love it and have great support.

"It's always a surprise when the reigning champions goes out and it puts pressure on the rest of us.

"It's tough [playing against a friend], Stan played great especially in the first two sets, until he started to really struggle with his fitness.

"He was hitting it so well so I had to wait for my chance. It's hard against a friend because we know each other's game so well and I wish him all the best for the rest of the season, because he has been great so far this year."

Federer will meet either Nadal-slayer Nick Kyrgios or Canadian serving machine Milos Raonic in the semi-finals. On Court One, the Australian wildcard is at it again, taking the first set on a tie-break. Raonic, however, is a break up in the second.

John McEnroe
Three-time Wimbledon singles champion on BBC TV

"Everyone is standing and these two deserve it. Wawrinka won a lot of fans in Australia and he has won a lot more today for that effort. Wawrinka had a great chance and Roger really had to use all his skill and guile to win that one."

Mirka is on her feet, Stefan Edberg is on his feet, the whole of Centre Court is on its feet, applauding as Federer heads off via the signing of a few novelty tennis balls. Three quarter finals done before 18:30 means there's time for some more action - the staff have dug out the doubles net.

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This time! Roger Federer smashes into open court and raises his arms before the ball bounces on the other side of the net. The King of Wimbledon is through to the last four, vanquishing his Swiss compatriot Stan Wawrinka. Centre Court rises to acclaim. Other champs may have fallen, but Roger remains.

And chance number three goes a begging. Federer long, Centre murmuring. What will it take? We'll find out. Here comes matcho number four.

What. A. Game. Wawrinka has Federer in the front row with a cross-court backhand. Eventually, the seven-timer runs out of puff and can't chase any more.

Deuce, but the serve not returned. Chance number three.

What is that return? Federer is charging but has to deal with a ball back on hit bootlaces. Net. Deuce. He'll get another chance, though. Setting up camp at the net, Wawrinka is chasing thin air.

You could turn your back on the tennis and know that Federer has saved. A smash does the business, the ball thudding into the green wall. Serve and volley, chip, Wawrinka wide. Match point number two...

Can you believe this? Wonderful rally. Both men at the back of the court, side to side. Wawrinka long? No. Here comes Fed. The dink. Into the net! Deuce.

Oh my word, Federer shanking a backhand. Break point...

Here we go. Wawrinka misses a bread and butter backhand. Match point.

Does Federer really need the help of the netcord? He gets it anyway, with Wawrinka then pushing a crosscourt forehand wide. Oh, Roger, what's that all about? Wild forehand. 30-30.

It's not just the backhand, you know. Wawrinka's forehand can also be silky, even if the serve and volley that follows is pretty ropey. Still, it's a hold to 15. Wawrinka can do no more with the balls on his racquet. Now, he must break if he is to make a first Wimbledon semi. Roger Federer, the seven-time Wimbledon champion, is to serve for the match.

It's close on Court One but the Australian bandwagon continues as Nick Kyrgios takes the first set against his fellow big server Milos Raonic, the eighth seed. The Fanactics very happy with their man's performance.

Federer has his nose pointing to the sky, sniffing out the win. Wawrinka has his chin to the floor, wondering how he can stop the Fed Express. When Federer is long for 30-30, the crowd murmurs. Centre supports Roger, but after this there will be nothing to watch. Wawrinka has his chance, a backhand into open court missed, but a Federer shank takes it back to deuce. Drama? No. Federer does the necessary meaning Wawrinka must serve to stay in the match.

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Wawrinka continues to fight the good fight, not giving Federer an unblocked route to the last four. He whips through the hold then, out of respect, gives his opponent right of way in the criss-cross at the net en route to the chairs. Towels gathered, balls of the Fed racquet, ready to go again.

John McEnroe
Three-time Wimbledon singles champion on BBC TV

"A lot of things are turning Roger Federer's way at this stage. None more so than what has happened elsewhere. Rafael Nadal being knocked out is a big plus because he trails the head to head to him but he won't play him and Murray has gone too, so he will only have to meet one of the other top three if he is to win it."

A Federer-Wawrinka backhand duel is like watching two swordsmen battle over the fair maiden. Federer all flowing locks and flowing right arm, Wawrinka facial air and flourishing follow-through. As if magnets are pulling them, they are drawn to the backhand side, trading blows. In the end, it's Federer's. Two games to go.

Andrew Castle
Former British number one on BBC TV

Image source, PA

"This is not a match for those who want to see beautiful rallies and beautiful tennis. This is going to be industrial.

"It will be staccato and there will be fleeting chances and it will be a question of who will take them."