Mats Wilander had just finished practicing and was relaxing in the cool of the locker room. Half a dozen rackets lay at his feet, as did several pairs of tennis shoes. He was deep in conversation. The subject: The U.S. Open pool in which Wilander, the No. 3 seed, had thrown a dollar.

"If I get one ahead of you, I'll pick all the same as you," he was saying to a locker room attendant, a wicked grin on his face. "If I beat you, I don't care about beating anyone else."

As Wilander continued to discuss strategy for the pool, Boris Becker walked in. "Becker, look at this," Wilander said, tossing a shoe toward him. "That's soft, you won't fall so much."

Becker caught the shoe, mumbled several obscenities at Wilander and threw it back as Wilander and Joakim Nystrom, his buddy and doubles partner, giggled.

Wilander threw the shoes into his locker, wiped the smile off his face and said to a waiting reporter, "Sorry you had to wait."

Always polite, always cooperative, that is Mats Wilander. But the public Wilander is very different from the private Wilander. Jokes are for the locker room among friends. They stop at the door when the public is looking in.

"I don't need the attention," he said. "That's not why I play tennis. I have fun playing tennis and I understand that the good things from tennis go hand in hand with attention. But it's not important to me."

Exactly what is important to Wilander is a mystery to all but a few. At 21, he is the No. 3 tennis player in the world. Only Jimmy Connors (eight) and John McEnroe (seven) have won more Grand Slam titles than Wilander (four).

He is, in short, a major talent. In fact, he is so talented that McEnroe and Connors openly wonder why he isn't even better, why he doesn't push himself the way they do.

"If you are that good, if you have that much ability, why not put in the little bit extra to be the best?" Connors asked. "The guy is a great tennis player, but being No. 3 seems to be okay to him. I don't really understand that."

Wilander smiles coyly when the question is raised. He has heard it before. McEnroe brought it up in Europe this summer and again Saturday, saying, "There are times when the guy just doesn't give 100 percent."

Wilander doesn't dispute this. He admits that earlier this year he was bored with tennis and not motivated to play. He admits that he worries about burning out the way Bjorn Borg did.

"But I am not like Borg," he said. "Borg had an American attitude, which I think is not so good. He only enjoyed winning and he was out of tennis when he was 26. I enjoy the tennis. I want to win, but I don't live for it."

He simply doesn't burn the way others do. Borg used to talk about winning being like a drug, as something one became addicted to. Connors has always talked about hating to lose. Wilander tries hard, accepts victory or defeat and then goes out and has a good time.

"Mats doesn't like to have pressure on him," said Yannick Noah. "He's No. 3 in the world and nobody knows him and he likes it that way. He just sneaks around quietly and wins a lot."

When he burst into the tennis world's consciousness in 1982 by winning the French Open at 17, he was labeled a Borg clone. After all, he was strictly a base-line player, he hit with lots of topspin and, speaking English, he started every sentence by saying, "For sure."

Three years later, he has emerged entirely different than Borg. His English is far better and those who have traveled the tennis circuit for years say he is very bright and thoughtful.

He has even changed his game, becoming more of a serve-and-volley player. He is a superb athlete.

It is his thoughtful approach to tennis, his unwillingness to become driven by the game, that leaves McEnroe and Connors, and even Noah, questioning his desire. Wilander understands that others can't understand.

"To me, there are only a few tournaments that are important," he said. "The Grand Slams, Davis Cup, the Swedish Open; that's about it. I always want to win when I play, but sometimes I just can't get that interested all the time. I want to keep playing for a long time. I don't want to happen to me what happened to Borg.

"If I got to be No. 1 in the world, that would be great. But if not, it's okay. If one of the other Swedish players passed me and became No. 1, I would be happy for him." He paused and the grin flickered. "As long as no one in my family passes me, I'm happy."

Borg left the game largely because he could not deal with not being No. 1. When McEnroe surpassed him, beating him in two Grand Slam finals in 1981, Borg walked out of the U.S. Tennis Center and into retirement.

It is impossible to envision Wilander doing that. Yet he worries about becoming like Borg. Borg was almost a recluse, spending time only with his wife and his coach. Wilander revels in the Swedish team concept.

Saturday night, when Nystrom walked off the court, the first person to greet him was Wilander, who had been watching the match. When Wilander won a tournament in Boston this summer, he devoted his victory speech to telling fans they should wish Nystrom luck because his wife was about to have a Caesarean section later that day.

"I just like knowing I have people to go out with every night," Wilander said. "If I hadn't been part of the team, maybe I would have gotten used to being alone, but right now it would be hard for me."

He has little trouble finding companionship, male or female. With his curly brown hair, hazel eyes and easy smile, he is a renowned lady-killer. But he is also popular with other players.

"He is completely the opposite of Borg," said one Swedish journalist. "Borg wouldn't even play Davis Cup unless he was paid. Mats still plays for his home town club (in the southern Swedish town of Vaxjo) for nothing, just because he feels he still has a commitment."

Behind the stoic attitude, Wilander is an underrated competitor. It is no coincidence that his first tournament victory was a major -- the French Open. It is no coincidence that when he played a meaningless Davis Cup match last month with Vijay Amritraj -- the team outcome had been decided -- he lost, then turned around and beat him in straight sets here.

And yet, Wilander still shrugs off questions about being No. 1, about winning here. "I don't expect to win here," he said. "I have a chance, but this is not my best surface or tournament. This is an American tournament in every way."

The wicked smile crossed his face for a second. "All the Americans love this tournament -- except for (Kevin) Curren." Curren is an expatriate South African who became a U.S. citizen in March and suggested after losing here last week that the U.S. Tennis Center could be improved markedly if someone dropped an A-bomb on it.

Wilander doesn't love the place, either. But he doesn't let it bother him. Few things bother him. But impassive as he may seem as he goes from one tournament to another, there is another side of him.

In July of 1982, when he had just turned 18, he and McEnroe played one of the greatest Davis Cup matches. It was the fifth and deciding match of the tie and the two of them dueled in torrid heat for 6 1/2 hours. Finally, McEnroe's experience won out.

Wilander had never cracked a smile, never shown any emotion during the match. He shook hands calmly and walked into the locker room. There, according to his friends, he sat down and cried.

He cried in private. There was no need for the public to know just how much he cared.