LONDON, United Kingdom (AFP) — Eight-time champion Roger Federer was sensationally knocked out of Wimbledon yesterday, surrendering a two-set lead and a match point at the hands of South African giant killer Kevin Anderson.

Defending champion Federer, chasing a 21st Grand Slam title, lost a Court One epic, 2-6, 6-7 (5/7), 7-5, 6-4, 13-11 as 32-year-old Anderson became the first South African in the Wimbledon semi-finals since Kevin Curren in 1983.

“Down two sets to love I tried my best to keep fighting. Beating Roger Federer here at Wimbledon will be one I remember, especially in such a close match,” Anderson said.

“I kept telling myself to keep believing. I said today is going to be my day.”

In a nail-biting four hour and 13 minute classic, it was 36-year-old Federer’s earliest exit at the All England Club since his shock second-round defeat against Sergiy Stakhovsky in 2013.

“Sometimes you don’t feel good and you try your best. Today (yesterday) was one of those days. I didn’t see it coming,” said Federer.

“I think it went in spells a bit also, how I was able to return his serve.

“I had moments where I was great, I felt like I was reading his serve, other moments where I don’t know where the hell I was moving to.”

Eighth seed Anderson will play 2016 runner-up Milos Raonic or American ninth seed John Isner on Friday for a place in Sunday’s final.

Three-time champion Novak Djokovic, meanwhile, reached his first semi-final at the majors in more than two years by seeing off Japan’s Kei Nishikori 6-3, 3-6, 6-2, 6-2.

The 12-time Slam champion will face world number one Rafael Nadal for a place in the final.

For only the second time at Wimbledon, Federer was beaten after holding a two-set lead, with his previous loss from that position coming against Jo-Wilfried Tsonga in the 2011 quarter-finals.

The 20-time Grand Slam champion appeared to be moving towards his fifth-successive Wimbledon semi-final after taking the opening two sets.

That initial burst gave Federer 34 successive sets won at Wimbledon, equalling his own record set between 2005 and 2006.

But, playing on Court One for the first time in three years, Federer was unusually error-prone.

Anderson had failed to take a single set off Federer in their previous four meetings.

Yet once he had ended Federer’s run of holding serve for 85 consecutive games — a streak dating back to last year’s semi-final — Anderson’s confidence soared.

Only once before had Federer played more games at a Grand Slam, and on that occasion he prevailed 16-14 in the 2009 Wimbledon final against Andy Roddick.

But this time Federer cracked, serving his first double fault at 11-11 in the decider to give Anderson the crucial break that ushered the Swiss to the exit door.

Djokovic reached his eighth Wimbledon semi-final and 32nd at the majors after a stormy Centre Court clash against Nishikori.

It will be the 31-year-old Serb’s first semi-final at a Slam since the 2016 French Open when he completed the career Grand Slam.

The 12-time major winner prevailed despite picking up two code violations and accusing umpire Carlos Ramos of “double standards”.

“I think the first warning was unnecessary,” said Djokovic, who was sanctioned in the second set for spearing his racquet into the court.

“It didn’t harm the grass. Kei did the same in the fourth set but wasn’t warned.

“The umpire said he didn’t see it. I don’t think it’s fair, but it is what it is.”

Despite his anger — and picking up a time violation in the fourth set — 12th seed Djokovic still reeled off 10 of the last 12 games.

Nishikori was bidding to become the first Japanese man to make the semi-finals in 85 years.

“Well, maybe wasn’t my best, but I thought I was playing good enough,” said Nishikori.

“But he was making me run all the time. Especially with his backhand, he can go both ways. That gave me real trouble.”

Nadal, who has made the quarter-finals without dropping a set, takes a 10-5 winning record over Del Potro into his quarter-final.

Two-time Wimbledon champion Nadal, who is chasing an 18th Grand Slam title, won the pair’s most recent clash in the semi-finals of the French Open last month.

He allowed the giant Argentine just seven games in Paris.

The 32-year-old is playing in the last eight at the All England Club for the first time since finishing runner-up to Djokovic in 2011.

Nadal is bidding to reach a sixth Wimbledon semi-final and 28th at the majors.

Del Potro, the 2009 US Open champion, is trying to reach the semi-finals for the second time, five years after losing to Djokovic in the longest last-four match ever played at the tournament.