WIMBLEDON, England ? Crack!

That’s what Andre Agassi heard on the way out of Wimbledon, the sound Mark Philippoussis’ racket made as it smacked serve after unreachable serve Monday.

Undaunted by the game’s greatest returner, who also happens to be ranked No. 1 and owns eight Grand Slam titles, the unseeded Philippoussis hit a record-tying 46 aces and upended Agassi, 6-3, 2-6, 6-7 (4), 6-3, 6-4, in the fourth round.

“So little can decide each set that it’s pretty frustrating at times,” said Agassi, the 1992 champion. “I felt like I made him earn it. I made him play the big shot at the crucial time, and he came up with it.”

His exit means no past winners are in the quarterfinals; that hasn’t been the case at the All England Club since 1973, when a player boycott diluted the field.

For Philippoussis, who had lost six straight matches against Agassi, this represents a return to the big time. Once ranked No. 8 and the 1998 U.S. Open runner-up, he fell out of the top 100 in 2001 after a series of left knee injuries. He’s always had that booming serve, though.

Broken twice in the second set Monday, Philippoussis won the last 16 games he served, saving nine break points. Only Goran Ivanisevic, in 1997, had as many aces in a Wimbledon match.

“The great thing about the serve is you’ve got the ball in your hands. You can take your time, no one can rush you. You’re in control,” the 48th-ranked player said. “Even on the second serves, I went for them. Against a guy like Andre, you have to.”

He earned his fourth trip to Wimbledon’s quarterfinals, having made it that far in 1998-00. He lost each time, once to Agassi, twice to Pete Sampras.

Australia's Mark Philippoussis reacts as he wins a point against Andre Agassi. Philippoussis won their fourth-round match in men's singles, 6-3, 2-6, 6-7, (4-7), 6-3, 6-4, Monday at Wimbledon.

Philippoussis, who surfs four hours a day when home in San Diego, will play a less-distinguished foe this time: Alexander Popp, who’s ranked 198th and beat Olivier Rochus, 5-7, 6-3, 6-4, 6-2.

Other quarterfinals: No. 5 Andy Roddick vs. Jonas Bjorkman; No. 4 Roger Federer vs. No. 8 Sjeng Schalken; and Britain’s Tim Henman vs. Juan Carlos Ferrero or Sebastien Grosjean — their match was stopped because of darkness with Grosjean ahead 2-1 in sets.

Wimbledon is the only Slam that schedules all 16 fourth-round matches on the same day. After rain delayed Monday’s start an hour, the Williams sisters, Jennifer Capriati, Lindsay Davenport and Kim Clijsters were in action. They all won quickly, dropping a total of 23 games.

Venus Williams had to be the most satisfied. She picked up a 6-1, 6-3 victory over No. 16 Vera Zvonareva, who stunned her in the French Open’s fourth round.

“Venus was unbelievable today,” Zvonareva said. “She didn’t give me chances.”

Today’s women’s quarterfinals: defending champion Serena Williams vs. No. 8 Capriati; 2000-01 champion Venus Williams vs. 1999 champion Davenport; No. 2 Clijsters vs. No. 27 Silvia Farina Elia, who never made the quarters at 43 previous majors; and French Open champion Justine Henin-Hardenne vs. Svetlana Kuznetsova.

Davenport will try to snap a five-match losing streak against Venus; Capriati has lost seven straight against Serena.

“The level will jump quite a bit tomorrow — the level of opponents,” Davenport said. “The top players have gone through relatively unscathed so far.”

The same can’t be said for the men. With defending champion Lleyton Hewitt a first-round loser, and second-seeded Agassi gone, it’s the first time in the Open era neither No. 1 nor 2 made the last eight.

“I had nothing to lose,” Philippoussis said. “Everyone was expecting him to win. That’s a great position to be in.”

Agassi appeared to be in great shape after taking the tiebreaker by adjusting to a 115 mph offering, reaching wide and — letting out an “Aaahhh!” — ripping a cross-court forehand return winner.

But, like Agassi, Philippoussis knows how to fashion a comeback.

At Wimbledon in 1999, the 6-foot-4 Australian, then 22, took the opening set off Sampras, but hurt his left knee and quit.

His 2002 season ended in August, after hurting the same knee during the U.S. Open. About a month ago, Philippoussis dumped coach Peter McNamara and returned to working with his father, Nick, who taught him to play tennis at age 6.

“We went back to basics, simple as that,” Philippoussis said. “That’s my thought process on court — just think about what I used to do when I was younger.”

He cranked second serves at up to 120 mph and surprised Agassi with all-of-a-sudden winners. In the second set, Philippoussis broke to 2-0 in a game that featured four aces (Agassi finished with 10), six deuces and six break points.

Agassi had three break points at 4-2, but Philippoussis produced five straight service winners or aces. Acknowledged Agassi: “Not much I could have done.”

The fifth set was similar. Philippoussis picked up the lone break in the seventh game when he drilled a shot deep and Agassi’s backhand sailed long. Philippoussis had to bear down in the next game, facing two break points, one set up by a double-fault (he had 12). Again, Philippoussis’ serve saved him: service winner at 128 mph, ace at 129 mph, ace at 128 mph.

“He’s always had the game,” said Roddick, who beat No. 12 Paradorn Srichaphan, 6-4, 3-6, 6-3, 6-2. “As long as you have a serve like his, you’re going to be in matches.”

While Philippoussis’ problems were physical, Agassi went through a period where tennis wasn’t a priority.

Recommitted, he worked his way back to win four more majors and, at 33, was hoping to become the oldest Wimbledon champion in the Open era. While many of his contemporaries are calling it quits, Agassi plans to return at 34.

“Why wouldn’t I be back? I’m still a tennis player,” Agassi said. “This is the place to be.”