Wawrinka is in a mood as dull as the light, showing no emotion as he come from behind to lead 40-30. Federer, though, is energised, transported to his own body, but a decade ago. A sprint and chip forces Wawrinka to play another two points, but that's the lot. Fans stand, Wawrinka leans over his own knees. Illness, or the thought of another defeat by his Swiss mate? Probably both.

John McEnroe
Three-time Wimbledon singles champion on BBC TV

"It looks to me like whatever Wawrinka was given to take earlier has made him feel worse not better. He is really struggling to compete out there."

Mirka Federer doesn't look like a mother who has many sleepless nights with her two sets of twins. Granted, she's hiding behind sunglasses the size of satellites, but she's pristine as she watches her man serve behind the break. Kicking dirt up as he scampers, Federer gets through the hold to 30. That's the game. If he holds, Roger wins.

Image source, Getty Images

Roger Federer doesn't run around court, he glides. When he gets to the ball, he doesn't hit it, he caresses it. All sliced backhands and arrowed forehands, Federer forces two break points. Match on the line here? Both men pushed back, ball being forced to travel miles, Federer out of position but Wawrinka goes long! Federer has the break in the fourth set and those blue-blazered new umpires might not be here for long.

Federer is cooking, sprinting in behind his serve in a white blur of headband and shampoo-commercial hair. Hold in an instant, pressure back on Wawrinka, who will bash down with new nuts.

Andrew Morris:, external Federer & Djokovic showing Andy Murray how to fight through adversity. Though you wonder had Murray won that second set tie-break...

Sarah:, external I'm fairly sure Federer's exercise regime consists mostly of ballet.

Beth Routledge:, external It's not over for Wawrinka yet…

Andrew Castle
Former British number one on BBC TV

"It will be interesting to see how much Kyrgios has emotionally in the tank after his win over Nadal. He needed to come through a bit of fire in that sixth game to hold serve and it was a good test for him."

If Stan is under the weather, it's not showing in his tennis. He holds to love to virtually no reception, both men stood still in the centre of their respective baselines at the end of the game, as if to move would be a sign of weakness. Eventually, Federer whips a ball to the ballboy and heads up the other end.

Roger is giving it the double teapot. Hands on hips, not a happy 17-time Grand Slam champion. He skips, stretches, still no Stan. Wait a bit longer...here he comes, looking a combination of peaky and hacked off. Not a great deal of Swiss love out there. Wawrinka to begin the fourth.

Federer won 85% of points when he got his first serve in in that third set, which he did 83% of the time. That's a serving performance that is pretty tough to resist. He's back on court, prowling the baseline, but Wawrinka is nowhere to be seen. Crowd restless, clapping impatiently.

Image source, PA

Five games, eight aces, line judges cowering at the back of the court.

It is all on serve out on Court One and may be for some time.

Image source, AFP

That will do nicely. Serve and volley, put the overhead away to leave him floundering. Roger Federer sits down with a 2-1 lead, Stan Wawrinka takes an age to return to his seat. A word with the umpire, then both men are off the court. Federer is a set away from another Wimbledon semi-final, a set and two wins away from an unprecedented eighth title.

Federer stands in the dirt, a beach in a sea of green grass, bounces the ball and cracks down an ace. Wawrinka won't lie down, engaging in baseline conversation, but a long backhand and another Federer ace bring two set points...

Is Stan looking cooked? A little forlorn? How can that backhand ever look done for? A thing of natural beauty, a flourish down the line tells Federer he won't get this set the easy way. Wawrinka holds his end of the bargain, Federer must serve it out to take the lead.

Tennis cliche number 54. It's only a break if you hold afterwards. Federer has written his own book on tennis laws, mainly surrounding winning whilst looking like the coolest man on the planet. Rapid hold, Centre clapping like seals, Roger one game away from the third set.

John McEnroe
Three-time Wimbledon singles champion on BBC TV

"Wawrinka is disgusted by that there. He will be thinking he should never have dropped his serve. It's been a long time coming but Roger Federer is finally in front here but Stan is struggling with illness. You have to try not to think about but it's hard to overcome that when you are playing someone this good."

Take that. Roger Federer is in charge of the second set thanks to the sort of forehands that should be protected by the National Trust. Taking advantage of an opening provided by a Wawrinka error, Federer whips a forehand down the line, arcing the green ball around his compatriot. Two breaks points, only one needed when Wawrinka is sent the wrong way. Huge "come on" from the seven-time champ. He's a break up in the third.

Image source, Getty Images

Singing might be a bit overstating the case, but the Australian fans - known amongst themselves and others as the Fanatics - linked arms and made a noise approximating to Waltzing Matilda before the opening game.

Nick Kyrgios did them proud as well in the opening exchanges, taking Milos Raonic to deuce before holding his own serve.

Number 19 seed Sabine Lisicki,, external who was beaten earlier by Simona Halep: My Wimbledon journey is over for this year but guess what... I will be back even hungrier next year!!! @Wimbledon. Thanks for the love you all give me here! Makes me feel like I'm at home! #cantwaitfornextWimbledonalready

The sun is trying to break through, casting a shadow from Federer as he bounces in preparation to serve. That ball he was once oscillating is back past him a flash to give Stan a sniff of a break. A sniff? Snuff it out. Three times Wawrinka fails to keep it inside the lines.