For Ivan Lendl, there is no escaping the nightmare. The plot is almost invariably the same: Grand Slam tournament. High-stakes tennis. Disappointment. Embarrassment. Defeat.

He never wakes up from this nightmare. It just goes on and on.

Today, on Centre Court, he departed Wimbledon in the fourth round, buried under a flurry of winners by unseeded Henri Leconte, 3-6, 6-4, 6-3, 6-1. That Leconte won was not shocking. He had played superbly all spring and Lendl had looked shaky and unsure of himself in the first three rounds.

What was shocking -- sad, in fact -- was Lendl's lack of resolve when he fell behind. After the French Open final, winner Mats Wilander commented that Lendl had gotten "nervous and tight" when behind. Leconte used the same words today.

In the men's locker room, crowded around two television sets as Leconte flicked winners past Lendl, players used a different word: choke. After his victory in the French Open final over John McEnroe a year ago, Lendl seemed to have shed that label. But four Grand Slam events later, he has reacquired it.

"When he is behind, his game changes," Leconte said. "You can see it in him. When I see it, it gives me more confidence."

"I was searching for something," Lendl said, "trying to figure out what I was doing wrong. There is not much I can do when he is hitting winners off my serve. When that happens, I don't enjoy the game. Against other players, I see him missing shots all the time. Against me, he forgets to miss."

Wednesday, Leconte will play Boris Becker, 17, the West German who has become the story of this tournament. Today, Becker came from 2-1 down in sets against Tim Mayotte for his second straight five-set victory.

Becker, coached by Leconte's former coach, Ion Tiriac, survived a break point at 5-5 in the fourth set, won a tie breaker despite spraining an ankle with Mayotte serving at 5-6, then won the match, 6-3, 4-6, 6-7 (5-7), 7-6 (7-5), 6-2.

"I didn't play that well today," Becker said. "I was lucky to win. In the fifth set, my ankle hurt a little, so I just kept going for big shots. I got them."

One year ago, he tore tendons in the same (left) ankle during a third-round match against Bill Scanlon. "When I went down, I thought, 'Oh God, not again,' " Becker said. After winning the tie breaker, he was able to take a break and have the ankle taped.

Mayotte joined the list of victims who predicted the youngster is not yet ready to win the tournament. But with Lendl gone, Becker has as good a chance to reach the final as anyone else in the lower half of the draw.

As impressive as Becker was, Leconte's victory overshadowed all other events on a humid, sun-splashed day that began with John McEnroe and Chris Evert Lloyd breezing into the quarterfinals with straight-set victories and ended with Leconte's masterful upset.

McEnroe, yet to be tested, should get his first tough match Wednesday against Kevin Curren. Curren, South African born but now a U.S. citizen, served his way past Stefan Edberg today, 7-6 (7-4), 6-3, 7-6 (7-3).

The winner of that match probably will find Jimmy Connors waiting for him in the semifinals. Today, Connors easily beat Sammy Giammalva, 6-3, 6-4, 6-3. He next will play qualifier Ricardo Acuna, who beat another qualifier, Robert Seguso, 6-4, 7-6 (7-4) 6-2. Acuna, who faced two match points in the first round of qualifying, is in the quarterfinals at Wimbledon as the No. 133 player in the world.

Almost as remarkable is the story of Anders Jarryd. Even though he is the fifth seed, he had not won here before this year and was down two sets and a service break in the first round against Claudio Panatta. But he escaped that match and today moved into the quarterfinals with a 6-3, 6-3, 6-1 victory over Danie Visser.

He will play Heinz Gunthardt, who has moved through the draw almost unnoticed. Today, Gunthardt won, 7-5, in the fifth set for the second straight day, this time beating Vijay Amritraj.

On the women's side, Evert (a 6-0, 6-4 victor over Anne Smith) and Martina Navratilova (a 6-2, 6-2 winner over Renee Uys) continued to make the game look easy. Navratilova will play doubles partner Pam Shriver in the quarterfinals.

Shriver survived her third three-set match of the tournament today, beating Steffi Graf, the 16-year-old West German, 3-6, 6-2, 6-4, in what might have been the best women's match of the tournament.

Graf is a true whiz kid, a long-legged belter who hit ground strokes from both sides with unabashed gusto. For a set today, she had Shriver off balance, often catching her in no-man's land and passing her.

"She really doesn't have any weakness back there," Shriver said. "She just stands back there and whales away."

Shriver began to figure out Graf in the second set, picking her spots to come in and using her 5-foot-11 height to take control of the net. Graf, frustrated by Shriver's reach, began missing shots she had been nailing.

Shriver broke Graf early in the second set, attacking her second serve, chipping the ball often to try to make Graf, as she put it, "dig the ball out of the grass."

Graf came back in the third set, hanging with Shriver until 4-all. Then, Shriver took command, serving to lead, 5-4, then getting to match point with an overhead. Then Graf sailed a forehand long and it was over.

"I'm just glad to get through it," Shriver said. "I'm really looking forward to playing Martina. I've had three tough matches, but I've held my seed (No. 5). Now I can just go out and hit out and see what happens."

That is just what Molly Van Nostrand did in her 7-5, 6-2 upset of fourth-seeded Manuela Maleeva. Maleeva never threatened to win. She is a clay court player without the speed or power to win on grass.

But Van Nostrand, ranked No. 155 and a qualifier who had not played a tournament in three months because of a foot operation, had every reason to be overjoyed after reaching a quarterfinal match with Zina Garrison. Garrison has not lost a set so far and today was a 6-1, 6-3 winner over Catherine Tanvier, who earlier had upset Gabriela Sabatini.

The other quarterfinal will pair Kathy Rinaldi and Helena Sukova. Each has won four matches without losing a set. The winner probably will play Evert, assuming she can beat Barbara Potter. Making a comeback at age 23, Potter today beat the last British hope in the tournament, Jo Durie, 7-6 (8-6), 6-7 (5-7), 6-1.

Leconte had eliminated John Lloyd, the last British men's player in the field, in the third round. Having won four of seven matches against Lendl before today, he came in confident. And, with the Centre Court crowd firmly behind him, Leconte, after a slow start, began timing Lendl's serve.

"I know how to play against him," Leconte said. "If he is serving his best, there is nothing you can do. Starting in the second set, he began missing and I could see he was getting upset. I knew I had a chance."

Leconte, who will be 22 Thursday, long has been marked for stardom. He is an all-or-nothing player who has learned patience under the recent tutelage of Patrice Dominguez, who also coaches Yannick Noah. "I have learned when to go for the big shot," Leconte said.

That was evident at the French Open when he outlasted countryman Noah in a four-hour, five-set masterpiece to reach the quarterfinals. Today, less patience was needed, but the shot-making was just as brilliant.

Leconte won the second set by breaking Lendl at love in the 10th game, ending with an angled backhand volley. He won the third set with two breaks, the second when Lendl could not dig out a forehand return at his feet.

By now, Leconte owned Wimbledon. Lendl was sulking, bickering with umpire Mike Lugg -- he was warned for his conduct at one juncture -- and watching the winners whistle past.

Leconte quickly broke for a 2-0 lead in the fourth set when he crushed two service returns, one a backhand, the other a forehand. Lendl revived briefly to break back, but Leconte reached back for a little more, breaking again with a backhand return that Lendl, lunging, punched wide.

That was the match. Leconte broke again to lead, 5-1, and Lendl slammed the ball he had mis-hit in disgust. Leconte served out the match at love, delicately dropping a forehand volley over the net on match point that Lendl just watched.

"It was a great feeling to beat such a good player at Wimbledon," Leconte said. "I am excited about the rest of the tournament. I think I have a chance. I feel good."

He felt wonderful as he left the court, blowing a kiss to wife Brigitte and waving to all sides as he departed. Lendl, ever the gentlemen, waited until Leconte was ready to leave and then walked side by side off the Centre Court that has been his undoing on so many occasions.

"What can I do?" he wondered. "I'm trying my best. I'm working hard. I'm doing better in Grand Slams than before I won the French last year, because I've got one now. I wish I had 10, but I don't."

Once, tennis people thought he might win 10 before he was through. He is 25 now. In tennis, that is not young. Undoubtedly, as he departed the grounds tonight, that thought occurred to him.