LONDON, JULY 9 -- Stefan Edberg has a face from a magazine ad and the body of a teen idol. With it he exudes the vivaciousness of a clerk. But he also is the Wimbledon champion, a title that so excited him for a few bold moments, he bared his chest on Centre Court.

After defeating Boris Becker over five sets in Sunday's final for his second title at the All England Club, the tidy Edberg peeled off his sweaty shirt to teenaged screams. Abashed, he hastily put on a fresh one -- the wrong way. Suddenly he rose and flung the shirt into the crowd.

Is Edberg, the shy, unprepossessing, 24-year-old Swede, developing a personality?

"No," he said. "It was maybe once in a lifetime."

He is self-effacing, either unaware of or embarrassed by his perfectly blond good looks, and humorous only in a deadpan, unintentional sort of way. Edberg also is the most elegant grass- and all-court player of his generation.

Ranked third and playing more convincingly than he has before, Edberg must be regarded in a new and more important light: as the chief threat to No. 2 Becker and No. 1 Ivan Lendl and fully capable of taking over the top ranking. If Lendl is the hardest working and most consistent of them, and Becker the more expressive and inspired, Edberg is potentially the most complete, with a grace of movement the others don't possess.

"If anyone tells me Stefan Edberg is boring, I'll tell them they're mad," said his coach, Tony Pickard.

Edberg has assumed his new role with steady work and without any great announcement, since 1985 slowly building a record that on Sunday became suddenly impressive. He has four Grand Slam titles with two Australian Opens and two Wimbledons, was a runner-up in the French Open and Wimbledon in 1989, and twice has been a semifinalist in the U.S. Open. In the last six months, he has twice defeated both Lendl and Becker to win tournaments, at the Masters last winter in New York, and now here.

"I always felt I had the potential to be up there," Edberg said. "But it hasn't been until the last two years that I got very close. Now it's really in reach."

Edberg has perhaps been held back by his own lack of conviction. In 1983 he swept the four major junior titles and was heralded as the coming great player. In 1985 he won his first Grand Slam title, the Australian Open. But he had been somewhat of a disappointment since, save for his '88 Wimbledon victory. He was overshadowed by countryman Mats Wilander, who was No. 1 in 1988, and by Becker, who holds a 15-9 lead in their series and beat him four times in six meetings last year.

The past season and a half marked a frustrating period in which Edberg seemed to run into invisible walls. In the '89 Australian, he strained a back muscle after reaching the quarterfinals. He unexpectedly reached the French final, only to lose to 17-year-old Michael Chang in five sets. Becker swept him in the Wimbledon final and Jimmy Connors beat him in the round of 16 at the U.S. Open.

"I was number three, I was making finals, but I wasn't winning," he said.

His foul luck continued at this year's Australian, when he was forced to retire from the final against Lendl because of a strained stomach muscle. Then he was upset in the first round of the French Open by Sergi Bruguera of Spain. After that loss, Pickard sat down Edberg and gave him what he called a verbal "kick in the pants."

Finally, this Wimbledon may have given Edberg a last measure of self-assurance. While critics said he was too subdued and unambitious and ignored him in favor of Lendl and Becker, Pickard reminded him that he had beaten both players back-to-back at the Masters. Edberg passed the tournament relaxed and almost unnoticed, as he commuted from the Kensington apartment he shares with girlfriend Annette Olsen. Edberg's confidence grew with each match and long before he dismissed Lendl in a shockingly one-sided semifinal, Pickard told his wife that Edberg would win.

"There have been four stages in his career," Pickard said. "When he won his first Australian, he knew he could live with those fellows. Then he won his first Wimbledon, proof that he could live with anybody, anytime. The Masters was the third stage, I believe he then realized he could possibly be the best player in the world. This Wimbledon is the fourth stage; his confidence has got to soar. He has to believe he can be number one. There's more to come."

What remains to be seen is whether Edberg has the inner resources to unseat Lendl and Becker regularly. His composed on-court demeanor can drift into lifelessness. He trailed Becker by 3-1 in the fifth set Sunday with two horrendous double faults before he gathered himself with a fist-shaking display of emotion.

"Maybe that's why I won, because I got fired up," he said.

Sometimes his inner calm helps him, sometimes it may hinder him, a confusing trait.

"What's important to me is just being myself," Edberg said. "I know I play my best tennis when I don't show emotion and what's going on in my head. And then sometimes I feel the need to show it. I very, very seldom get angry."

Off the court, Edberg is vastly more outgoing than he was as a teenager. Now he is at least a self-possessed, easy smiler capable of making a joke or two.

"In character he's grown enormously," Pickard said. "Seven years ago he'd have sat here and yes and no'd you all morning."

That does not mean Edberg, no matter how high he reaches, will ever be flamboyant. He is a homebody who may perform so well at Wimbledon because he can move through it quietly. Crowds should not expect another shirt-throwing episode.

"They had better keep that shirt," Edberg said. "There's not going to be many around."