LONDON — Obliged to hit the road and make the exotic trek to No. 1 Court at the All England Club, Roger Federer probably did not realize that his journey Wednesday had only just begun.
What looked at first like another straightforward, straight-set victory over Kevin Anderson, the big-hitting South African veteran, eventually morphed into a five-set Wimbledon upset for the ages.
By the end of this quarterfinal, a stiff drink seemed more appropriate than a serving of strawberries and cream. Nerves and serves were severely tested in the afternoon sunshine, but Anderson, a 32-year-old who has cracked at such moments in the past, was the one who held firmest this time.
After saving a match point in the third set, he rallied to win, 2-6, 6-7 (5-7), 7-5, 6-4, 13-11, and record what felt like the biggest victory of his long career — quite a statement for a man who reached the US Open final last year.
“Down two sets to love, I really tried my best to just keep fighting,” said Anderson, the No. 8 seed. “And I was able to scrape through that third set and the fourth set, and by the end, I felt I did a great job not thinking about things too much.”
The top-seeded Federer double faulted for the first time in the match when serving at 11-11, 30-30. Anderson broke him on the next point and then served out the match, taking deep breaths between deliveries as he had throughout the 4-hour, 14-minute duel.
About five hours later, Federer’s rival and foil, second-seeded Rafael Nadal, survived a five-set spectacle against fifth-seeded Juan Martín del Potro, 7-5, 6-7 (9-11), 4-6, 6-4, 6-4.
Anderson had 28 aces in the match, but he is not just a big server. He can produce huge pace from the baseline as well, and he ultimately needed a combination of skills and a great deal of mental strength to reach his first Wimbledon semifinal.
In four previous matches against Federer, Anderson had not won a set. Federer, an eight-time Wimbledon champion, had not lost a set here since his five-set defeat to Milos Raonic in a 2016 semifinal.
It was only the fifth time in Federer’s career that he lost a best-of-five match that he led, two sets to none. The last time was at the semifinals of the US Open in 2011 against Novak Djokovic.
Entering Wednesday, Federer had a 32-set winning streak at Wimbledon. He extended it to 34 against Anderson, but then the wheels began to come off.
Federer’s forehand, which had been so sharp in the early going, started producing errors. His serve, which had been practically infallible through three rounds, was broken three times.
Still, Federer had a match point in the third set with Anderson serving at 4-5. And he was up by 0-40 on Anderson’s serve two games later and could not convert any of the break point opportunities. He won only 3 of 12 break points on Anderson’s serve in the match. Anderson didn’t even face a break point in the fifth set.
“It’s one of those average days you have to try to win the match,” said Federer, referring to his own level of play. “And I just couldn’t get it done today so it’s disappointing.”
He said he did not believe that playing on the No. 1 Court instead of Centre Court was a factor in the defeat.
“I don’t think it really mattered, to be honest,” he said. “I had my chances. That’s my problem, really.”
On Friday, Anderson will play another big server, John Isner of the United States, who defeated Milos Raonic, 6-7 (5-7), 7-6 (9-7), 6-4, 6-3, to reach his first Grand Slam semifinal at age 33.
Djokovic also advanced to the semifinals, defeating Kei Nishikori, 6-3, 3-6, 6-2, 6-2. Djokovic, a 12-time major champion, had not reached the final four of a Grand Slam event since the 2016 US Open. He missed the second half of last season with an elbow injury.
Djokovic will play Nadal in the semifinals.
When asked if he thought he was flying under the radar at this tournament, Djokovic said, “I’m really not thinking about being an underdog or being a favorite. I just try to build the momentum. Obviously I’ve been very pleased with the way I’ve played so far on the grass court season.”