NEW YORK, SEPT. 7 -- It all seemed so simple. The dream quarterfinal matchups that everyone had hoped for before the U.S. Open began were about to become reality.

Ivan Lendl had won in straight sets and so had John McEnroe. That was matchup one. Jimmy Connors, hobbling on a bad foot, had outfoxed Henri Leconte in four sets. All that was left was for Boris Becker to finish off Brad Gilbert tonight to create matchup two: Becker-Connors.

Becker was up two sets and a service break, leading 3-1. "I was having an easy time out there," Becker said. "I was happy with the way I was playing. Then I served two double faults and all of a sudden it all turned around."

In what seemed like an instant, Gilbert and Becker had reversed roles. Gilbert was the aggressor. Gilbert was hitting winners. And Becker was a teen-ager who looked out of place in the fourth round of the U.S. Open.

By the time it was over, Gilbert had scored a 2-6, 6-7 (7-4), 7-6 (7-4), 7-5, 6-1 victory, ending Becker's Grand Slam season in shocking fashion.

Becker failed to reach the quarterfinals in three of the four Grand Slams, with the exception being the French Open, where he reached the semifinals on clay, his weakest surface.

"It was just a very difficult year for me," Becker said. "After Gunther {Bosch} left me {after the Australian Open in January}, people kept waiting for things to go wrong because I did not have him coaching me anymore. I was hurt by a lot of things that were said as a human being. I guess the pressure just got to me."

Tonight, Gilbert got to him. Once he broke with the aid of Becker's double faults to get back to 3-2, Gilbert was a different player. Following some advice from his brother, Gilbert began to work on Becker's forehand -- which was erratic to say the least.

"The one break really got me back in it," Gilbert said. "Once I won the third-set tie breaker, I really felt like I was on a roll. Then the fans got behind me and that really pumped me up."

The fans had come pouring into the grandstand once McEnroe finished off his 6-4, 7-6 (7-2), 6-3 victory over Andres Gomez. Two days after the outburst that cost him $17,500 and a two-month suspension, McEnroe's behavior showed only one small flaw (throwing his racket after a double fault). His tennis was almost as good. Other than one stretch in the second set when he let Gomez break back three times, he controlled the match -- and himself.

"I didn't try to control myself tonight any more than I have in the past. I tried to control myself the other day, too. I'm happy with my tennis and happy to get a shot at Lendl, but I'm sorry that the other thing happened."

McEnroe said he was almost certain he would appeal the fines and suspension after the tournament but didn't really want to discuss them now. "I'll weigh my options then," he said. "I'm sorry this happened now. It's been a little tough to concentrate with my baby due so soon {Friday} and all. I feel bad about this because it's tough on her {his wife, Tatum} and on my family. If it was just me, I wouldn't mind so much."

The story of the day, until Gilbert began his comeback, had been Connors. Throughout the tournament, he has struggled with a foot injury. He has what amounts to a blister on the ball of his right foot and five doctors have been unable to tell him what is causing the problem or what will cure it.

"For five days it didn't bother me at all," Connors said. "Today, it hurt whenever I moved. But I wasn't going to quit out there. This is the U.S. Open and it only comes once a year. I'm 35 and I don't know how many more years I'll play here. I would have played today on a peg leg."

He might have found a way to win if he had. Leconte is a little like McEnroe, blessed with left-handed genius and an often magic touch but cursed by an eccentric personality. But instead of manifesting itself in a bad temper, his shows up in some wild shotmaking.

Today, he played a perfect first-set tie breaker, then lost his serve three times in the second set. He had five break points in the second and third sets that he did not convert. Then in the fourth set, even with Connors needing treatment from the trainer, the old man just ran away, finally winning, 6-7 (7-0), 6-4, 6-4, 6-3.

"I wish I could have a bad foot," Leconte said, "if I would be able to run like him."

Connors talked at length after the match about looking forward to a match with Becker. He will have to wait.

Buoyed by the fans, Gilbert, who turned 26 last month, began playing perhaps the best tennis of his life. He had break points in the eighth and 10th games of the fourth set, but Becker still had a few big serves left.

But serving to put the set into a tie brekaer, Becker got hit by a sucker punch he never really saw. Gilbert made an extraordinary get of a forehand volley on the opening point and Becker was so surprised, he never moved for the ball.

Gilbert turned wild-eyed after that. He crushed three straight winners, the last a running forehand, and the set was his. As it turned out, so was the match.

"At 5-all in the fourth, I was dead tired," Gilbert said. "But the crowd really gave me a boost. I saw the American flag waving and it was sweet."

By now the crowd was in a frenzy. With all the troubles American tennis has had of late, this had become catharsis. Gilbert was playing in a trance. Becker was in a different sort of state: total exhaustion. "I just had nothing left for the fifth set," Becker said. "I have played very long matches all week."

Gilbert was blasting from all sides and Becker had no answers. In the second game, he double-faulted twice, the last one on break point and Gilbert had control. He never looked back. Becker won six points in five games and looked as though he might lose the last set at love as he did to Gilbert five weeks ago in Washington.

But he showed some courage by winning a four deuce game to make it 5-1. Gilbert quickly served it out, though, with two service winners to get to match point and then watching a Becker forehand sail wide. Gilbert leaped in the air, arms aloft and was still celebrating when Becker came around the net to congratulate him.

"This is about as big as I've had," said Gilbert, who is in a Grand Slam quarterfinal for the first time. "It's the greatest feeling I've ever had in tennis. The fifth set, I felt like I had him but I knew I had to stay aggressive to finish him."

He finished him and finished a year Becker will want to forget quickly. "Everyone will say, 'what a bad year, what a bad year,' " Becker said. "It was, but it wasn't. Being number four is not so bad. It was a mental thing, though. Here, I wanted to win so much because it was the end of the year and this was my last chance."

Becker, upset as he was, managed a weak smile. "One good thing is that I'm 19 and not 32. I'll be back."

But not this week. Instead, Gilbert goes on to play Connors. . . who isn't 32 either. TODAY'S FEATURED MATCHES DAY

Stadium Court -- Helena Sukova (6), Czechoslovakia, vs. Claudia Kohde-Kilsch (9), West Germany; Mats Wilander (3), Sweden, vs. Ken Flach, Sebring, Fla.

Grandstand Court -- Stefan Edberg (2), Sweden, vs. Jonas Svensson, Sweden; Miloslav Mecir (5), Czechoslovakia, vs. Mark Woodforde, Australia. NIGHT

Stadium Court -- Martina Navratilova (2), Fort Worth, vs. Gabriela Sabatini (8), Argentina; Andrei Chesnokov, Soviet Union, vs. Ramesh Krishnan, India.