Boris Becker won a tense duel between the heirs apparent of tennis today, enabling West Germany to tie Sweden at one match apiece in the Davis Cup final.

Becker, 18 and ranked sixth in the world, beat 20-year-old Stefan Edberg, No. 5, in a textbook display of fast-court tennis. Becker and Edberg, 1985 victors at Wimbledon and the Australian Open, respectively, traded powerful serves and slashing returns for 44 games before Becker won, 6-3, 3-6, 7-5, 8-6.

In the first singles match, Mats Wilander gave Sweden, the defending champion, a 1-0 lead when he beat Michael Westphal, 6-3, 6-4, 10-8. The doubles are scheduled for Saturday, with two final singles matches Sunday.

Edberg, the only top Swede who has built his game around serve and volley, was given at least an even chance against Becker. Edberg thrives on pace, and at Munich's Olympiahalle, both the green carpet and fast-bouncing Pirelli balls seemed as well suited to his game as to Becker's.

Yet the husky young German not only won the duel of power hitters but also proved better able to bunch the passing shots needed to break serve. He won the pivotal third set by hitting four winning returns in the 12th game, then raced to a 4-1 lead in the fourth set on the strength of 11 consecutive points. One of those 11 gave a glimpse of Becker as a potential world champion: a lob volley played from the shoe tops, followed by a drop volley winner.

That play carried Becker to a 5-2 lead, one game from victory. But Edberg survived match point and then, aided by two Becker double faults, tied at 5-5. It was Edberg's final charge. At 7-6, with Edberg serving, Becker hit two outright winners to go up, 0-40, then a third to take the match.

Becker made his customary winning gesture -- clenching both fists in front of his chest. He embellished that by trotting around a part of the court, bullfighter style, racket raised high above his head. The crowd of 13,000 roared appreciatively.

At the overflow news conference that is now standard after his matches, Becker was applauded by numerous German journalists. "I had to hit those (winning) returns," he said of his dazzling defensive play. "Stefan is playing the best tennis of his life, and after McEnroe, I think he's now the best serve and volleyer."

Asked if he expects Edberg to be his "main competition" in the future, Becker replied, "for the next 20 years, yeah." He was laughing as he said that, but not much.

The West Germans badly wanted Becker to play the opening match, in hopes that he would get the team off to a rousing, victorious start. Instead, the draw gave the first match to Westphal, 20, a gangling, curly haired Hamburg native who is 51st in the computer rankings. Westphal's opponent: Wilander, fourth in the rankings, winner of 19 of his 24 Davis Cup matches, and as cool a competitor as can be found in big-time tennis.

Wilander demonstrated how much his game has expanded and matured since he won the French Open as a pure baseliner in 1982. He served a dozen aces, volleyed deftly and pressed Westphal into repeated errors.

Said Westphal, more in observation than regret, "I said before that if we (West Germany) were to have a chance, I had to beat Wilander. So now I've lost . . . And we'll see what happens."

Becker's match was interrupted briefly in the final set by demonstrators against apartheid in South Africa.

They threw leaflets demanding freedom for jailed black South African civil rights leader Nelson Mandela, and criticized links between Bavarian Gov. Franz Josef Strauss, who was attending the match, and the South African government. Police hustled several protesters out of the sold-out Olympiahalle.