One year ago when John McEnroe left Madison Square Garden, the tennis world wondered if he might be on the verge of taking his place as possibly the greatest name in tennis history.

This morning, he left here with the tennis world wondering if his days as the world's No. 1 player might be finished forever.

He had already slipped to No. 2 before he took the court for what should have been a routine first-round match against Brad Gilbert in the Grand Prix Masters tournament. A little more than two hours later, McEnroe walked off the court beaten and embarrassed, a 5-7, 6-4, 6-1 loser to a player who had won one set from him in seven previous matches.

"What can I tell you?" McEnroe said, "I'm embarrassed."

Also confused. Since he destroyed Ivan Lendl in straight sets a year ago to wrap up a tennis year in which he won his third Wimbledon, his fourth U.S. Open and his third Masters, McEnroe has been as enigmatic on the court as he has been for many years off it.

He lost in the French Open semifinals to Mats Wilander -- in straight sets. He was humiliated in the quarterfinals at Wimbledon by Kevin Curren -- in straight sets. He was blown away by arch-rival Lendl in the tournament he once owned, the U.S. Open. Again, straight sets.

Through it all, McEnroe mused publicly about the pressures of being No. 1, about how his relationship with Tatum O'Neal had changed his approach to tennis, how he wasn't certain he had the drive to stay on top any longer. Last week, he commented that he now felt he had two full-time jobs: tennis and his relationship with O'Neal, who is expecting their child in May.

His inconsistent year dropped McEnroe behind Lendl in the rankings but, before Wednesday night, he was still clearly the world's No. 2 player. Now, having exited early here, he is much closer to dropping behind Wilander and Boris Becker than he is to catching Lendl.

The match against Gilbert was the kind McEnroe previously never would have lost. He won the first set and should have been in command. But he let Gilbert back into the match in the second set and began to lose his composure. At one point, as the two men changed courts, McEnroe told Gilbert, "You don't belong on the same court with me."

Gilbert made certain McEnroe didn't have to stay on the same court long, winning the last six games in the final set. As has often happened in the last few months, McEnroe's play became listless and discouraged when he got into trouble.

"Give him credit. He played the match of his life," McEnroe said. "I'm just not moving as well as I normally do. I'm not serving as well, I'm not hitting the ball as solid, I'm making too many mistakes and my concentration isn't what it used to be to do well in a tournament like this."

In short, McEnroe is having serious problems.

After the Wimbledon debacle, McEnroe said he had to get into better shape. He worked hard last summer but said again after the Gilbert match that he is not in good shape. He will be 27 next month. In tennis, that makes McEnroe old -- the average age of the current top 10, even including 33-year-old Jimmy Connors, is 24.2 -- and given his new life with O'Neal, everyone on the tour wonders if he will regain his drive.

Gilbert, like most players, prefers to look at McEnroe's current problems as a slump. "Even Wayne Gretzky has slumps," he said. "John is still only 26."

But at this stage, McEnroe is -- by his own admission -- a confused and disoriented 26. Since Wimbledon, he has admitted that all the off-court questions raised by his relationship with O'Neal have bothered him. In Australia in November, he pushed a reporter and spat at a photographer when they hassled him about O'Neal. He also, for the first time in his career, ducked a postmatch press conference after losing a shocking five-set quarterfinal to Slobodan Zivojinovic.

Wednesday night, he was more like his old self, patiently answering questions even as midnight approached. But he had no real answers.

"I've had a lot of great experiences here and I'm just embarrassed at the way I played because this is a great place. It's just that my attitude is bad. I let things affect me that other times don't."

McEnroe was affected by the small crowd pulling for Gilbert. He was affected by problems with his service. He was affected by his lapses of concentration. He was affected by all the same things that never seemed to bother him when he was dominating the game.

The question for McEnroe and tennis now becomes whether he can put all the problems behind him, whether he can hone in again on the kind of play that made him a magician on the court, a player whose skills and touch and verve were such that even those who criticized him for his behavior had to concede that he was a special tennis player.

Can McEnroe regain his desire to be No. 1?

"The desire is there," McEnroe said, "but right now it isn't."

With that, he was gone, leaving his listeners just as confused as he appears to be.