Boris Becker, the tennis wunderkind, comes up against Team Sweden Friday when West Germany seeks to win its first championship in Davis Cup history.

Becker looms as the key figure as the 72nd Davis Cup final gets under way. On his beefy frame rests whatever chance West Germany has of defeating a Swedish squad that in 1984 humbled the United States.

Two of the Swedish team's players, Mats Wilander and Stefan Edberg, have won half of this year's four Grand Slam events. Wilander captured the French Open, and Edberg, two weeks ago in a major surprise, won the Australian Open.

Yet depth counts for little in Davis Cup, where one powerful player can virtually win the title. West German captain Wilhelm Bungert is hoping Becker can do just that when he plays Edberg in the first match Friday and plays doubles with Andreas Maurer Saturday.

Their Swedish doubles opponents have not yet been announced. The deadline for announcing doubles teams is one hour before the match.

Friday's second singles match will be Wilander against Michael Westphal. They trade opponents for Sunday's singles.

West Germany has gone tennis mad since Becker won this year's Wimbledon championship at the age of 17, the youngest man ever to do so. West Germany has rarely before had a sports hero of such magnitude. In polls testing name recognition, Becker routinely outdistances the nation's political leaders.

Since Wimbledon, Becker has won only one major tournament, the Cincinnati warmup for the U.S. Open. In his last outing, at the Australian Open, he suffered an embarrassing second-round loss to No. 188 on the professionals' computer, Michiel Schapers of the Netherlands.

However, Becker has an excellent Davis Cup record. In nine Cup matches this year, he has lost only twice, once in singles and once in doubles. In the quarterfinal round, he raced through the United States' fill-in singles choices, Eliot Teltscher and Aaron Krickstein, without losing a set. He also won both semifinal singles against the Czechs, who were playing without Ivan Lendl, No. 1 in the world.

So far Becker's strengths -- a booming serve, strong ground strokes and decisive net play -- have generally overcome his two major shortcomings. One of these is footwork. Built more like a tight end than a classic tennis champion, Becker does not move well.

The second shortcoming is mental: the ability to overome frustration and vary his game to make it more effective. Becker so far is little more than a hitter. On a fast surface, that type of game will beat all but the best opponents.

Afer his loss to Schapers in Australia, Becker's manager, Ion Tiriac spoke of his pupil's need to control his anguish and change his style when necessary. Tiriac is forcing Becker to learn hard lessons by playing on all surfaces. And for now that might bring all sorts of losses.

In this sense, the Davis Cup final should be pure joy for Becker. The West Germans have built, in Munich's Olympiahalle, a carpet court that Wilander today called "the fastest I've seen in Davis Cup play."

But the Swedes are far better fast-court players than they often are credited with being. Edberg is an instinctive serve and volleyer, and Wilander has developed an attacking game that puts him at home on any surface.

Further, Edberg is coming off the biggest victory of his life, in Australia. "We've already conceded two singles matches to Edberg," Bungert said today. "We feel Wilander is the weak link.

"We'll have to be lucky to win. When our players play well, the Swedes seem to play better."