"By the end I thought I did a great job".
"It was just one of those days where you hope to get by somehow", said Federer, who last played at No. 1 Court in 2015. He had brushed aside all four challengers en route to Anderson, including winning the first set of his Round 4 match against Adrian Mannarino in just 16 minutes. He hit 28 aces against Federer, saved nine of 12 break points and managed to hold his own in the rare lengthy baseline rallies.
Federer's serve had been untouched in the tournament until Anderson, who won just one receiving points in the opener, took it in the second game of the second set.
The Spaniard came through a mammoth encounter with Juan Martin del Potro yesterday, making the final four for the first time in five years after a five-set clash which spanned almost five hours.
When Anderson broke in the second set it was the first time the Swiss had dropped serve at this Wimbledon.
Should Nadal win Wimbledon, on Federer's preferred surface (grass), then the balance of power between the sport's greatest rivals may be shifting.
Anderson then served it out, ending things with a 205kph service victor, and raised both arms overhead.
While Federer started out strong, besting Anderson 6-2 and 7-6 in the first few sets, his dominance became less complete as play went on.
How rare was it that Federer would lose after holding a match point in a major? Inevitably, the match went the whole length and then some more, until Anderson grabbed the only break-point in the entire set.
Federer didn't seemed bothered by being away from Centre Court when he cruised through the first set in just 26 minutes. "I don't think it's fair but it is what it is". "That's my problem really".
Next up for Anderson is a semi-final on Friday against either John Isner, the ninth seeded American. Djokovic defeated 24 seed Kei Nishikori in four sets on Wednesday at Wimbledon, 6-3, 3-6, 6-2, 6-2, to advance.
But the 20-time grand slam champion dug deep to his heels as he lifted a bullet backhand pass to overtake at 4-2 before he escaped his predicament with a fierce forehand that forced Anderson's return to fly long.
Djokovic has improved in every tournament in 2018, making it to the fourth round of the Australian Open, the quarterfinal round of the French Open and now the semifinal round at Wimbledon. "I was in the flow of the match", eighth seed Anderson said. I love this sport and I've been working hard and smart to get into shape for the big events, and nothing gets bigger than Wimbledon.
"I always say I was in the same position, it's not easy coming from South Africa, it's very far from the tennis scene".