Or was it the court?
The eight-time champion's quarterfinal with eighth-seeded Kevin Anderson is underway on No. 1 Court, after Federer was scheduled away from the All England Club's main stadium for the first time since the same stage of the tournament three years ago.
The match had all the makings of a routine Federer victory after the first set, which the Swiss great won with two service breaks and the loss of just one point on his serve.
He also holds a 4-0 career lead over 2017 US Open runner-up Anderson who has yet to take a set off the Swiss.
Federer ultimately paid the price for failing to convert any more than three of 12 break-point opportunities, including three in a row with Anderson serving at love-40 in the fourth set.
And he didn't stop there.
So much more. Federer was attempting to reach his 13th semifinal at Wimbledon and move closer to title No. 9, both of which would have broken his own records. It looked like another smooth Federer ride when he bagged the first set against Anderson 6-2 in 26 minutes.
His absence paves the way for his arch rival, Rafa Nadal, to win a third Wimbledon title, which would narrow the Grand Slam gap between the sport's best players.
That meant Federer had equalled but not bettered his previous best set-winning streak which came between the third round in 2005 and the final in 2006.
He may well pause to take stock of a journey that started in Johannesburg with him gleaning as much knowledge as possible from global tennis magazines, cutting out articles on the sport's greatest rivalries, while pouring over the Grand Slams whenever they were broadcast on South African television.
Federer saved a set point in the fourth with a flying forehand but Anderson replied with a whipped victor of his own to ensure a decider would be needed. So far the four matches have been really, really good for me'. Obviously, it was important for me to get through those tight moments.
(Juan Martin) Del Potro, don't ever discount him, he's a guy who's won a Slam, won the US Open going back in 09 and got semis in the French.
Anderson had 28 aces in the victory, compared to Federer's 16 aces.
However, the 31-year-old Serbian raced through the third and fourth sets to advance in two hours and 34 minutes.
After a slump following two years of nearly total domination of the men's game, Djokovic's star appears to be back on the rise and he is a clear contender to win a fourth Wimbledon title.
Novak Djokovic admits he is "grateful" to Wimbledon for scheduling his quarter-final match with Kei Nishikori on Centre Court. It wasn't Federer's famous mental wandering that had cost him the match against Anderson. "I think one of the keys, especially in these Grand Slams, because they're two weeks in length, you have to try and keep up with some of your off-court maintenance, especially I think the strength work". After Anderson calmed down and lost a pretty tight second set, Federer's forehand started going wayward.
The 32-year-old South African, seeded eighth, said: "I feel the few times I've played him in the past, I've walked onto the court without the necessary belief that I needed to to get through the match".
He said: "I just asked the chair umpire how did I deserve that warning?"
"I don't know why Del Potro shouldn't think he has a great chance", Wilander said.