In a stunning turnaround in an unfamiliar setting - No. 1 Court instead of Centre Court - the top-seeded Federer blew a third-set match point and, eventually, all of his big lead in a 2-6, 6-7 (5), 7-5, 6-4, 13-11 loss to No. 8 Kevin Anderson on Wednesday in a 4-hour, 14-minute tussle.
Or was it the court?
In the third set, the pair were pegged on serve until a net error from Anderson opened the first match point at 5-4.
Federer, the five-time reigning champion, was cruising in the 2009 U.S. Open final (sense the theme), when he was thrown off his game by a combination of the raw, hard-hitting 19-year-old Del Potro and, of all things, computer technology.
He made the first statement of intent by cashing on two backhand errors by Federer and breaking the Swiss' serve in the second game of the second set.
And he didn't stop there.
It was the second time Federer dropped a two-set lead at Wimbledon - after a reverse to Jo-Wilfried Tsonga in 2011 - and the fifth time he lost at a major when holding a match point.
When quizzed about his extraordinary motivation to play Wimbledon every single season, he explained how much he hated losing at the grass-court Grand Slam tournament.
"I felt like I was just trying to keep myself very highly motivated, a lot of belief in myself and said "Today is going to be my day".
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"Yeah, of course, the goal is to come back here next year", said Federer, who has won three Grand Slams over the last two years.
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The teams have met 73 times before with Belgium winning on 30 occasions, France 24, and 19 matches drawn. "It's very good for Belgium ", she said.
Ramos then hit Djokovic with a time violation warning for taking too long to serve in the seventh game of the fourth set.
Federer was completely out of sorts by now and his uncharacteristic struggles on his forehand didn't improve in the fourth set.
Not that Anderson is anything other than an elite tennis player.
"I don't know how long it's going to take (to come out of this defeat)".
The Swiss lost the set in a flurry of aces, with Anderson's relentless, powerful serve sending the match into a decider. If it gnawed at him, there was no evidence as the match surpassed the four-hour mark.
Djokovic reached his eighth Wimbledon semi-final and 32nd at the majors after a stormy Centre Court clash against Nishikori. "The more I can just treat it like another tennis match, the better for me", Anderson said earlier in the week.
'Obviously that helps knowing what time you get out on the court.
"Well, maybe wasn't my best, but I thought I was playing good enough", said Nishikori.
The South African, who got to the US Open a year ago, said in the post-match interview that he just believed "today was my day". "I've actually been a little bit more aggressive this tournament in terms of some of the strength I've done on the off days, which I think has been beneficial", he said.
From there, the tall and powerful Anderson kicked on whilst Federer stalled.