By Pritha Sarkar
LONDON (Reuters) - When Roger Federer found himself sprawled face down on his beloved Wimbledon turf on Friday as a flying forehand winner from Milos Raonic whizzed past it looked like the "old guy" of tennis had nothing left in the tank.
In the midst of contesting his 10th tension-filled set in three days, it was clear time had finally caught up with the aching and ageing limbs of the 34-year-old Swiss supremo.
However, in a year when "one stupid move" sparked a chain of bad luck -- which included left knee surgery in February and then sitting out the French Open with a back injury -- Friday's fall in the semi-final could not have come at a worse time.
Instead of heading for the baseline after getting back on his feet in the fourth game of the fifth set, Federer slumped into his chair and started to rub down both legs with a towel.
The crowd started to chuckle, wondering if he was staging a sit-down protest as his dreams of winning an eighth Wimbledon title, and 18th major overall, started to slip away from him.
But for Federer it was no laughing matter.
The man who until 2016 had a body that seemed bullet-proof against the aches and injuries endured by most top athletes, waited to get the all clear to continue from the trainer as he had landed heavily on his left knee after rolling his ankle.
"I was insecure coming into Wimbledon," said Federer, who surged back from two sets and three match points down in the previous round before beating Marin Cilic.
"(But) the 10 sets I played the last two matches really gives me the belief that I'm tougher physically than I thought I was, he added after his 6-3 6-7(3) 4-6 7-5 6-3 defeat by Raonic.
"I just hope with the slip I had in the fifth, I'm going to be fine tomorrow and beyond. I hope I didn't hurt myself.
"Is it (the pain) a three-day thing, is it a 24-hour thing or is it more? I don't know at this point.
"I was able to finish. But I don't slip a lot. I don't ever fall down.
"With the body that's been playing up this year, I just hope I'm going to be fine. I believe I am, but I'll know more tomorrow when I wake up."
The only thing that is certain when he wakes up on Saturday is that he will not be contesting a record-extending 11th Wimbledon final -- and 28th overall.
Instead, he will have to digest the disappointment of losing a Wimbledon semi-final for the first time in his career.
Whereas outside Wimbledon the Swiss had a 17-12 win-loss semi-final record at the slams, at the home of grasscourt tennis he had a perfect 10-0 record -- until Friday's heartache.
What was particularly painful for Federer, though, is that he missed chance, after chance, after chance -- converting only one of nine break points that he fought so hard to earn.
Despite leading by two-sets-to-one and holding two break points in the fifth game, Federer's body simply let him down.
"Just don't remind me of everything," the third seed pleaded in his news conference.
"I had a break point, I don't know how many. It's something I want to forget about. Getting broken at 6-5, I can't believe I served a double-fault twice. Unexplainable for me really.
"Very sad about that and angry at myself because never should I allow him to get out of that set that easily.
"Then getting broken again at 2-1, having the slip. Very disappointing half an hour there for me.
"This one clearly hurts, because I could have had it. I was so, so, close."
A month shy of his 35th birthday, Federer knows time is not on his side if he wants to triumph at Wimbledon again, but he was adamant his goals stretched beyond the world's most famous Centre Court.
"It's a dream to win my eighth," said Federer, who applauded the fans and gave a thumbs up as he left his favourite arena.
(Reporting by Pritha Sarkar, editing by)