Mark Philippoussis has climbed higher personal mountains than those constructed by Andre Agassi on Centre Court. But in recent years no challenge to the Australian could have felt quite so satisfying. Johnny Watterson reports from Wimbledon

Written off as a realistic candidate to win or possibly survive the tournament due to chronic injury, Philippoussis contrived, with a blinding 46 aces, to serve up a game of such power and clout that even the best return of serve in the game was brow-beaten out of the competition.

The ace count, which reached 11 in the fifth set alone, matches that set by Goran Ivanisevic against Magnus Norman in 1997. The mind of Goran may explain how he perished in that match but Philippoussis, although consistently threatened by the 1992 champion, closed the shutters and weathered a furious, corrosive effort from Agassi in the final set.

That blank, almost morose, expression did not once change as the swarthy 51st-ranked player in the world held off repeated challenges from the 33-year-old American.

In the final count Philippoussis converted three service break-points out of 21 that he had earned. That's all he needed with his weapons-grade right arm that has now delivered 79 aces in four matches and is fast approaching the record set by Ivanisevic in 2001 of 212 aces for the competition.

The Australians win crashed into view from the most unlikely of sporting culs-de-sac, that of long-term injury.

Philippoussis's problems began with his left knee at the quarter-final stage of Wimbledon in 1999 and have troubled him ever since, frequently threatening to end his career.

Forced to have surgery on it three times in January 2000, December 2000 and March 2001, the 6ft 4ins outside hope finally ended up in a wheelchair and last year was having to have injections into his knee in an effort to create an artificial joint.

During that time the 26-year-old drifted in and out of patience with the game but finally made a calculated decision to try to fight his way back.

From his base in Southern California, where he'd been surfing more than playing tennis, Philippoussis finally hitched up with his father, Nick, again and "went back to basics". The father and son's reinvention of the wheel has now brought him to where he was three years ago, when he reached the quarter-finals.

"I just fought hard. He's beaten me twice this year and six times in a row, I think. But I'd nothing to lose today," said Philippoussis.

"Every match here I felt better and better. I've worked hard on my fitness all year and it's paid off, as simple as that. I did drills that have nearly made me cry. I thought about that work I did to get me here."

For Agassi it ends the recurring dream he has four times each year, the one where he tries to win another Grand Slam. But so too are there parallels with Philippoussis. Years ago Agassi also reassessed his life having firstly plummeted down the world rankings and out of sight before also deciding that tennis was the centre of his world. Agassi will be coming back next year and will be looking for the title.

"Sure, why wouldn't I be back next year," he said defiantly. "I'm still a tennis player. This is what I do. My plan is to be back.

"As you get older you become more aware of how short-term these opportunities are.

"When I was 22 I could have sworn I was in the middle of my career getting onto the latter stages of it.

"He's (Philippoussis) has had some unfortunate injuries. He feels now that his body is holding up, his head is in the right place. There's no reason why he can't do it.

"At one stage I was 141 in the world and that was a personal embarrassment. I had no business being out there competing. I had to decide to do it or not to do it. He's turned the corner and he's in the straight now."

The match hinged on slim margins. Just one break in the first set gave Philippoussis a 6-3 lead but Agassi responded immediately breaking "The Scud" twice in the second set. A tie-break then allowed the American nose 2-1 in front before Philippoussis again broke once to level the match 2-2. Finally one break in the fifth, where Agassi had four break points but could not convert, handed the match to Philippoussis.

"I felt we both were doing well to give ourselves the chances. I had my looks there," said Agassi. "So little can decide each set. He was definitely the better player at the right time. You always feel against a player like him that once you lose your serve, the set is kind of over.

"In the fifth I'd three break points at 3-3 and on second serve he hit at 120 m.p.h. There were a lot of moments where either one of us could have taken the match and he did it."

Philippoussis now plays Alexander Popp in the quarter-final while Tim Henman came through in a late match against last year's beaten finalist David Nalbandian. Henman easily claimed the first set 6-2 before dropping the second 6-7.

In fading light he again went ahead in the third 7-5 as once more he frustrated fans with sublime shots mixed with punishing errors. Finally the 10th seed took his third break point for the match 6-3.

Andy Roddick found safe passage in four sets against Paradorn Srichaphan and now plays Sweden's Jonas Bjorkman while Roger Federer survived being twisted and jerked by his physio during his match with Feliciano Lopez to also earn a quarter-final place.