Image source, AFP

Ball boys wait at the net, poised as if at the start of the 100m. Photographers are in pits on either side of the court, while line judges dressed like posh ice cream men wait for an error. Did I say the momentum has changed? What do I know. A Wawrinka service game speeds by in a blur.

Federer is starting to feel the love. A rapid hold, ended with a chest-baring ace. With Wawrinka struggling to hold last time out, has the momentum changed?

He doesn't look all sunshine and yodelling, but Wawrinka eventually holds. He stomps to his chair, head down on the turf. Not a happy Australian Open champion.

Federer is on to something here, two break points. Is Wawrinka feeling a bit dicky? He doesn't show it in saving one with a cheeky dink, then unleashes a smooth backhand to the corner for parity. Wawrinka, all fluffy hair and goatee, has the advantage with an ace, but falls back with a wild backhand. On we go.

John McEnroe
Three-time Wimbledon singles champion on BBC TV

"Wawrinka is not so much in charge now but he is still looking very good. He had a very good chance to win the second set and is playing very well. Right now though he is trying to weather the storm of the illness."

Federer, by the way, is biding to reach his 35th Grand Slam semi-final. His 34 is already a record. In reaching this 42nd quarter-final, he has passed the top mark he previously shared with Jimmy Connors. As Federer eases to a simple hold, the sun just dips behind a cloud, giving us some temporary cool.

Ooofff, are you allowed to do that to Sir Roger? With Federer at the net, a Wawrinka backhand is aimed straight at the seven-time champ's head, so hard it would have taken his headband off. Is all part of a simple Wawrinka hold. No sign of why the medical staff were needed.

Image source, Reuters

Novak Djokovic on his victory: "It was a tough five-setter. Coming in I knew Marin would play aggressively.

"He raised his game but I allowed him to come back into it. I was too passive on my strokes and he used his opportunities but I managed to find the right pace when I needed it.

"After I changed my shoes in the fourth set I played well - I will keep them to play Grigor Dimitrov. We could hear the crowd during the match and it was a bit distracting but no excuses we had to concentrate. It was a big win for Grigor and he hasn't lost on grass this year."

"Come ooonnnn!" is the cry as Federer advances to the net and dispatches the volley that levels the match. Centre cheers its approval, willing on its oldest hero. The subplot is that Wawrinka needs a visit from both the trainer and the doctor. "Can you give me something to stop Federeritis please?"

Even a Federer challenge is greeted by fist pumps and cheers in the crowd. Unsuccessful, Wawrinka has saved two. Now, though, Fed will serve.

American Taylor Townsend, who was beaten in the first round by Klara Koukalova:, external @stanwawrinka is playing amazing grass court tennis... The way he is taking the ball early is .... just wow...

Those Federer-sounding roars are getting louder inside Centre. Three set points.

So, now Djokovic is through, can Federer make it even more of normal service being resumed? Second-set breaker with Wawrinka, a mini-break wasted by the seven-time champ. We're even at 3-3 as they switch ends.

Peter Fleming
Seven-time Grand Slam doubles champion on BBC TV

"There were nervous moments - no mistake about that - but Djokovic overcame them to come through."

Image source, Getty Images

The number one seed survives a scare and is through to the last four. For just a little while it looked as though Novak Djokovic would come a cropper against Marin Cilic but, from a set behind, Djokovic was untouchable. With Murray and Nadal gone, Djokovic, if he wasn't before, is very much the man to beat. He'll play either Milos Raonic or Nick Kyrgios in the semi-finals.

Cilic nets, Novak hollers. Three match points.

Peter Fleming
Seven-time Grand Slam doubles champion on BBC TV

"There were parts of this match when Djokovic was surly and frustrated but those moments have passed and he is almost home now. These guys are great champions because they are strong mental gladiators and can concentrate for such long periods and it is hard to play against him."

Yep, like Usain Bolt in a race with Phil Taylor, Novak Djokovic is out of sight. A double break, a roar, and a frightful battering of the air with the right fist tells us the the world number two will serve for the match. Question, is Usain Bolt a better darts player than Phil Taylor is sprinter?

Grigor Dimitrov on the rise of a new generation: "We want to prove to the big guys that we are ready and want to establish ourselves. This is a good effort from us but you have to do it every single tournament to challenge the top four guys."

Grigor Dimitrov on his straight-sets win: "I wouldn't call it easy. It was a tense match because since the first ball we were both ready to win but still I got on top of him early on and that helped me.

Image source, Reuters

"It's a great feeling, I am proud of what I did. I am not surprised because it is something I have worked for - to be at this level and on a stage like that."