By Ian Westbrook
BBC Sport at Wimbledon
Roger Federer won a classic contest with Lleyton Hewitt 6-1 6-7 (1-7) 6-0 6-4 to earn a place in the semi-finals.
Federer has reached his second Wimbledon semi-final
The defending champion raced through the first set and the second was at 1-1 before a rain break, which helped Hewitt summon a recovery.
The 2002 champion played some spirited tennis before levelling the match, but again fell short in the third set.
He broke Federer in the fourth game but the Swiss showed why he is champion by breaking back and winning the match.
Federer goes on to face Sebastien Grosjean, who beat Florian Mayer in straight sets.
Fortunes changed dramatically during the match but during the first two sets and at the end of the fourth, Federer played at a level that Hewitt just could not match.
"It was a great start - it was good to be ahead against him," Federer told BBC Sport.
"He fought hard and there were a lot of rain breaks and I really had to fight.
"He played really well and it was tough to break him.
"In the third set Lleyton didn't play his best and I was serving well. We had a tough point to break eventually and I started to play unbelievable tennis.
"I've had very few matches on Centre Court which were battles and this was one of them, so it was nice to play such a tough match."
Hewitt conceded that Federer had played superbly but still felt he had missed some chances.
"It's Wimbledon, you're always going to be disappointed," said Hewitt. "I gave it everything I got, but I had a lot of opportunities.
"In the fourth set I was the better player but have very little to show for it.
"When he's confident, he's very difficult to stop.
"He's the best player in the world at the moment. He's a shot-maker. He came out and was on fire right from the start."