July of 1996 was the last time it happened. That was the last occasion Pete Sampras saw a match-winning ball being hit that was not played by him, that did not hand him the Wimbledon championship. That year it was Dutch player Richard Krajicek, yesterday it was a 19-year-old grass-court novice called Roger Federer playing his first ever match on Centre Court.

Federer's final explosive return on the Sampras serve has now changed the entire complexion of the career of the greatest grass court player of his generation and arguably the best in the history of the game. Sampras went out 7-6, 5-7, 6-4, 6-7, 7-5.

A year after the tearful champion ran to his parents after collecting his 13th Grand Slam title and his seventh Wimbledon title, he had set new sights. Bjorn Borg's run of five wins in succession was the most immediate. Another was the all-time record of seven Wimbledon titles which he still shares with William Renshaw. Those are no longer and even Renshaws ancient mark is more distant now than ever.

Sampras said he will return but as Goran Ivanisevic keeps being asked - which Pete Sampras will it be? In addition the Sampras aura of being the unbeatable, the pre-eminent player on grass has been exploded. His crown has slipped, probably irrevocably, and Sampras at 29 has been shown once again as a mere tennis player.

"You've got to give the guy a lot of credit for what he has done," said Andre Agassi reacting to the defeat after he sailed past Nicolas Kiefer in three sets to the quarter finals. "If you want to talk about something that's incredible it's how he's (Sampras) won this thing seven times.

He's been the toughest person to beat in the history of this tournament." The Sampras body language, which is generally doleful, was positively cadaverous as Federer's fifth set return whistled past him for the final point. The expression was more than one of mere surprise.

It was of shock, of trauma of gaping disbelief. It was only the second time the American number one seed h ad lost at Wimbledon since a quarter final defeat here in 1992. A staggering achievement unlikely to be beaten by anyone in the near future, Sampras was also seeking the 100th grass court win of his career, one that would have caused hardly a ripple on his $41,063,159 prize fund fortune.

Federer with one career title to his name compared to his opponent's 63, was not seen as the player to change the course of tennis history. "I'm disappointed. It will take some time to get over this," said Sampras.

"He won the big points, a couple of break points in the fifth. Today I came up a little short. It is a tough, tough loss to have to deal with. I wasn't going to last for ever.

" That was a close match and I've won a lot of close matches over the years." Federer, mild mannered and open was grateful for his opportunity if a little bemused by the magnitude of his win.

He now joins Martina Hingis on Switzerland's celebrity 'A' sports list. "It feels unbelievable," said Federer. "I went out trying to beat him but I knew it wouldn't be easy. In the end it was a great feeling coming out on Centre Court playing Pete Sampras, one of my former idols," he added, without feeling the weight of the word "former".

"Sometimes when I looked at the other side of the net and saw him, I just said is this true, am I really playing against him? But then it goes away, this feeling and you think about your serve. A lot of friends and players told me "this year I think you can really beat him." A few players, a few coaches, myself ... I knew I had a chance. That gave me a lot of confidence."

The first set went to a tie break which Federer, having been a set point down, won 9-7 to put Sampras under significant pressure. Unusually the Sampras serve was often being threatened but when the American broke to level 1-1 thoughts drifted to four sets from which the champion would advance to the quarter finals.

But Federer continued to yield little, serving strongly and volleying with all the panache and punishing accuracy normally associated with Sampras.

Federer also hit Sampras with huge ground strokes off both wings, gobbling up his first and second serves, probably his biggest weapons.

It was clear that the number one seed was uncomfortable, quite an irony given it was Centre Court, his "front room." Sampras broke back for the second, Federer missing an easy volley before claiming the third 6-4 and fourth on a tie break sending the match into five sets.

Federer was actually hitting more unreturned serves than Sampras - 51 per cent to 48 per cent, a critical factor. And when Sampras went into the fifth having to always serve to stay level the pressure mounted. At 6-5 he faltered. Going 15-40 down to give Federer two match points, the sparkling forehand return down the line finally ended the unequalled run.

Who will take it on now is less certain. Lleyton Hewitt will not, nor will Greg Rusedski. Crowd favourite Hewitt departed 4-6, 6-4, 6-3, 4-6, 6-4 to Frenchman Nicolas Escude in just under three and a half hours while Goran Ivanisevic continued to glory in his new found form with a straight set win over Rudsedski.

Rusedski, who had lost to Ivansevic on the previous eight meetings, never got to deuce on the Croat's serve and won only a total of 14 points against it in the entire match. Hewitt's demise may well have seen him running on empty.

"I actually felt fine. My fitness wasn't a concern," he said, having played three, four and five set matches in the previous rounds. "Pat (Rafter) is now my favourite to win it. I hope he does."

There Hewitt is not alone although Agassi once again looked unshakable.