WIMBLEDON, ENGLAND, JULY 2 -- It was a day of anticlimaxes, until a couple of journeymen Americans gave Wimbledon an unexpected drama. Boris Becker overwhelmed Pat Cash, Stefan Edberg did the same to Michael Chang, and left in the twilight was No. 7 seed Brad Gilbert, who defeated David Wheaton by the epic score of 6-7 (8-10), 3-6, 6-1, 6-4, 13-11 to reach the quarterfinals.

The round of 16 began with soaring expectations at the All England Club. Becker, Cash, Edberg and Chang were major champions with angry pasts, and surely they should have made more of their matches. Instead, defending champion Becker of West Germany beat 1987 titlist Cash of Australia routinely, 7-6 (7-3), 6-1, 6-4. Sweden's Edberg swept one-time French Open miracle Chang cleanly off the court, 6-3, 6-2, 6-1.

"I'm kind of frustrated, not because I lost but because I just didn't play," Chang said. "Just one of those days."

Chang, the 18-year-old seeded 13th who began the season recuperating from a fractured a hip, was not the same player who beat Edberg in a five-set French final last year. In his first meeting with third-seeded Edberg since then, Chang had his serve broken a fatal nine times. Cash too was taken aback by the ease of Becker's victory, and the brassy Australian could only take solace in his progress, steadily working his way back after severing his Achilles' tendon 14 months ago.

"I had chances and I couldn't get them," Cash said. "It's just a matter of playing some more of these matches until it comes right. It's hard to come back and beat a guy like him first time up."

The unseeded beneficiary of a wild card into the draw after a year off the circuit, Cash was physically fit but lacked an edge. He lost two set points in the first with errant backhands, and could not slow the imposing Becker's momentum afterward.

"When two players like us come together we know the first set is very important," Becker said. "And so after I won the first set it kind of clicked and it was much easier for me, and even more difficult for him."

What didn't materialize in those two matches did when Gilbert and Wheaton took the court. Few paid attention to them, because Gilbert hadn't won a first-round match in a Grand Slam event since 1988 until last week and Wheaton was a lean 21-year-old from Lake Minnetonka, Minn., unseeded and ranked 35th.

They embarked on a grudging argument that took 4 hours 10 minutes to decide and included 43 aces. After recovering from a strained groin and two-set deficit, Gilbert trailed by 2-5 in the marathon fifth and killed two match points, in the eighth and ninth games, before he finally won with a resounding ace down the middle to become Becker's next opponent.

"I just felt I was overdue to get some decent luck in a major," Gilbert said. "Now, I'm still in the event and anything can happen."

Gilbert tottered on the edge of upset throughout the match. Wheaton nearly broke his serve for the match in the eighth game, but pushed a forehand just wide. Wheaton gained a second match point at 40-30 in the next game, but Gilbert charged the net for a forehand volley and went on to break for 4-5.

Then came an interminable stretch in which they exhanged aces and volleys, neither gaining an advantage. It was a question of who would play a careless game, and it was Wheaton who finally did so in the 23rd. He killed one break point with a spinning backhand volley, then double-faulted to give Gilbert another.

They played the point of the match, Wheaton charging to the net and laying down a forehand drop volley. Gilbert reversed direction and scrambled wildly to push a gentle backhand slice down the line, passing Wheaton with a winner that touched the chalk.

"I did a U-turn," Gilbert said. "I just kind of snuck the ball by him there."

Wheaton perhaps was tired in his third straight five-set match. He made little pretense in the final game, even though Gilbert trailed by 0-30. "I think he was already shaking hands," Gilbert said. Wheaton never moved toward the final ace. He later gracelessly denigrated Gilbert's ability, and when asked if Gilbert had any chance against Becker, replied with a curt, "No."

"If we played again the outcome might be different," Wheaton said. "I should have won the fifth set. I believe I should have won it."

The only seeded casualty of the day apart from Chang was No. 11 Guy Forget of France, defeated by Christian Bergstrom of Sweden, 6-4, 3-6, 6-3, 7-5. Top-ranked Ivan Lendl made a hesitant escape from the clutches of unseeded Bryan Shelton in the continuation of a third-round match halted Saturday by darkness. Lendl trailed by a service break in the third set and never fully asserted himself over the hard-serving, 24-year-old former all-American from Georgia Tech, 7-6 (7-2), 6-7 (4-7), 6-4, 6-4.

Shelton's massive deliveries and the windy conditions had bothered Lendl Saturday night, and he was no more at ease today. Shelton had an opportunity to accomplish the upset of the tournament, but ultimately lost on nine gambling double faults. Resuming play in the third set, he broke Lendl for a 3-1 lead, passing the top seed with a silky backhand return. But he double-faulted twice in the next game to give it back, typical of the entire match.

"He was serving big, going for it, and in the end he paid for it," Lendl said.

Shelton took consolation in making some large strides. He was wracked by nerves in his first appearance at Wimbledon last year, with the bad luck of drawing Becker as his opening opponent, and lost in straight sets. He took a first-set tiebreaker off Jimmy Connors in the first round of the 1989 U.S. Open, only to lose the next three, 6-2, 6-2, 6-2. His performance here should push him into the top 100, and he has the knowledge that for a few minutes, he led Lendl.

"I think I had him flustered," Shelton said. "I think it's a little bit of a victory. I've finally overcome a few things, previously in big matches I had been nervous. I had chances. So it was big for me."

Becker and Cash had some bitter exchanges in their previous meeting here, Becker winning a 1988 semifinal in straight sets. So their match was expected to be entertaining if not close. Cash is working relentlessly to haul himself up from No. 142 in the world to his previous place among the top five, and some of his old swaying and prowling form has returned. But it all but ended after the taut first set.

Cash had an opportunity to make it an entirely different match as Becker served at 5-6. With a break point, Cash blocked a backhand return that curled just wide. A second break point went the same way, ticking just slightly off.

"He missed by not much," Becker said. "That's the difference between winning and losing."

Becker climbed all over him in the tiebreaker. He gained triple set point with two intimidating winner returns, a blunt forehand cross and then a sweeping low backhand down the line.

"It was the first time I'd played a guy in the top 10," Cash said. "It wasn't easy."