The 6-foot-8 Anderson wasn't broken in the final three sets.
1 Court for the first time since 2015 at Wimbledon played a factor, Federer added: 'I don't think it would have changed if I played there previous year.
Federer, 36, breezed through the opening set in just 26 minutes, had a match point in the third set and was just two points from victory a couple of times in the epic fifth set that lasted 90 minutes.
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.
He moved up to No. 10 in the world rankings in 2015 and later advanced to the final of the U.S. Open in 2017, where he lost in three sets to Rafael Nadal.More news: Cornwall woman takes vehicle for accidental, two-week joyride
"I felt good actually".
Roger Federer's Wimbledon win streak came to a shocking halt Wednesday.
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.
Federer, Wimbledon's greatest male champion, was greeted warmly Wednesday by Court One ticket holders who never imagined they'd have a chance to see him in person.
It's also the first time Anderson has knocked off Federer, the defending Wimbledon champion, in five tries.More news: Trump administration threatens tariffs on another $200 billion in Chinese imports
Emboldened by the development, Anderson went on all-out attack.
Having saved Federer's only break point of a 90-minute fifth set at 3-4, Anderson took his first chance at 11-11 and then served out for victory. However, when Anderson and Isner face off, there will be plenty of aces and quick points. There was no drop-off in intensity; no letdown in the quality of his play.
From there, the tall and powerful Anderson kicked on whilst Federer stalled. But the Swiss had a patch of bad luck, losing his footing and, as a result, netting a forehand form an off-balance position. In this picture, Nadal of Spain celebrates winning his Men's Singles fourth round match against Jiri Vesely of the Czech Republic on day seven of the Wimbledon Lawn Tennis Championships at All England Lawn Tennis and Croquet Club in London, July 9, 2018. If it gnawed at him, there was no evidence as the match surpassed the four-hour mark. At 11-11, Anderson broke Federer's serve once again before capping off the upset with another big right-handed serve.
And he closed, fittingly, on a service victor.
It was an extraordinary turnaround after Federer won the first set in 26 scintillating minutes against a player he had beaten four times out of four without dropping a set.More news: North Atlantic Treaty Organisation summit: Trump urges members urged to double defence spending
Isner will line up opposite Anderson on Centre Court in Thursday's semi-finals - the American won the battle of the big servers with Canada's Raonic.
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