Bjorn Borg completed one of the most masterful weeks any tennis player has ever enjoyed, extending his career-long domination of Vitas Gerulaitis, 6-2, 6-2, today to win the Grand Prix Masters Tournament for the first time.

Borg's speed afoot and the accuracy of his passing shots astounded a crowd of 17,642 spectators at Madison Square Garden and intimidated Gerulaitis, who has never beaten the 23-year-old Swede in 15 career meetings.

Borg broke Gerulaitis' serve in a dramatic, 24-point fifth game, after Gerulaitis had saved nine break points, and then accelerated to rout the flamboyant New Yorker in 1 hour 16 minutes.

Borg played like a million bucks, and the $100,000 first prize he collected for adding his first Masters title to the fourth French Open and Wimbledon crowns he won last summer pushed his total prize winnings for the 1979 season to $1,008,742.

As the final playoff for the top eight singles players and the top four doubles teams in the worldwide 1979 Colgate Grand Prix circuit of tournaments, the Masters is considered the climax of 1979 in prize money and record calculations, even though it is played two weeks into the new year.

John McEnroe -- whom Borg defeated, 6-7, 6-3, 7-6, in a superb showdown for the No. 1 world ranking in Saturday's semifinals -- finished the year with prize winnings of $1,021,745. The $40,000 prize he shared with partner Peter Fleming for winning the Masters doubles over Wojtek Fibak and Tom Okker, 6-3, 7-6, 6-1, on Saturday night assured McEnroe of the top position on the prize money totem pole.

But even though McEnroe won the WCT Finals (beating Jimmy Connors and Borg in consecutive matches) and the U.S. Open in 1979, there could be no question after this week as to the indentity of the No. 1 singles player in the world.

Borg began the week in devastating form, pulverizing Roscoe Tanner, who had ended his dream of a Grand Slam in the quarterfinals of the U.S. Open in a 6-3, 6-3 match.

Then he beat longtime arch-rival Connors, 3-6, 6-3, 7-6, in a scintillating match worthy of comparison with any previous in their grand rivalry. After trouncing Jose Higueras, 6-2, 6-0 -- losing only eight points on his serve -- Borg reached down into his incomparable wellspring of skill and nerve again to beat McEnroe in another final-set tie breaker, concluding a match as competitive and sublime as the jewel against Connors.

To top it all off, he made Gerulaitis -- who had looked like a prince in beating McEnroe and Connors both within 16 hours -- look like a pauper today. This was a command performance, worthy of a player who says that he would like to be remembered ultimately as the greatest player of all time, and is well on his way toward building a case for such recognition.

Asked to rate the importance of this Masters, Borg said, "i think I have to put the title very, very high, because I think maybe the best eight players in the world were playing in this tournament. I beat Tanner, Connors, McEnroe, Gerulatis, everybody, so it should rank very high . . .

"I prefer to win the title more than the money. To win $100,000 is great, for sure, but the title means more to me, especially because I never won the Masters before and never won a big title in New York before."

Borg had been in the Masters final twice previously -- in 1975 at Stockholm, and in 1978, the first year that outgoing sponsor Colgate brought it to New York -- but lost to Ilie Nastase and Connors. He had never won a tournament in New York in 12 tries, dating back to the 1972 U.S. Open.

"I just know that for the next five or seven years, however long I play tennis, I want to win the big titles. And then when I retire, I want to look back and see how many of those titles I won," said Borg.

In 1980, he will play a pared-down schedule and concentrate on winning a third consecutive French Open and a fifth straight Wimbledon singles, both of which would be modern records, plus his first U.S. Open.

"For sure you play scared but i feel very comfortable in big tournaments because I've done very well in them the last four or five years," he said. It's more difficult to stay on the top than to reach the top. The difference at the top is very small, and you have a lot of pressure on you because everyone wants to beat you."

Borg, however, has a remarkable record against his chief rivals at the uppermost echelon of the game. Consider this: he now has winning streaks of at least two matches over all the other players in the world top 10 for 1979.

He beat McEnroe in their last three meetings after starting the year 2-2. He beat Tanner twice after the U.S. Open loss. He has won seven in a row over Connors, 15 in a row over Gerulaitis, nine over Guillermo Vilas, two over Arthur Ashe, 13 over Harold Solomon, 10 over Higueras, and 13 over Eddie Dibbs. That gives Borg an aggregate record of 74-0 in his most recent meetings with the other best players on earth.

Today he said he felt a little stiff at the start, but he loosened up after winning that marathon fifth game, which became a lovely little match within a match.

Gerulaitis dug out from 0-40, and had two advantage points, but Borg kept applying the pressure, whacking the top-spin ground strokes he hit with such admirable pace and accuracy all day, sprinting for several "gets" that defied belief.

Borg got to break point for the eighth time on an incredible point. Gerulaitis made two spinning volleys that appeared to be sure winners, but Borg dashed first to his left to retrieve a backhand, then whirled and swooped to his right, getting to the ball just before it bounced for the second time. At full stretch he scooped a forehand deep to the baseline, and Gerulaitis -- also running like the wind -- hit a backhand that just clipped the net cord and fell back.

Gerulaitis got back to deuce with a high backhand volley, and got an ad with an ace. But then he overhit a forehand volley, could only make a futile grope at a Borg lob that hit just inside the baseline and ran away, and netted an awkward forehand volley from the service line off a mis-hit backhand return. With that first service break, Gerulaitis started to disintegrate.

Borg saved three break points in the next game, two of them with sizzling forehand passes down-the-line. After that, Gerulaitis only held serve once more, in the opening game of the second set.

"Those two games were very, very important, because after that I relaxed a bit," said Borg, who has a regular pulse rate of 35 and always looks as relaxed as a human being can be without being dead.

Gerulaitis agreed that the match turned from contest to execution in those fifth and sixth game. "A little bit of the air went out of the balloon after that," he said. "He got on top of me right there, and I never seemed to recover."

By the end, Gerulaitis looked forlorn. The lasting impression of this match is one of him scooting to the net, lunging vainly, and then abruptly whipping his head around, leonine blond mane flowing, as Borg's passing shots whistled by and the line judge gave the palms-down signal that the ball was good.

Gerulaitis, the third best player in the world, knows he cannot beat Borg from the back court -- no one can do that -- so he kept coming in behind chips and slices and floating returns of Borg's serves, even though he was getting passed left and right. Sometimes he came in behind second serves, and he was passed then, too.

The fleet Gerulaitis sometimes looks like the cartoon Roadrunner as he streaks in, almost threathening to outrun his soft approach shots and get to the net before the ball crosses it. He can get away with such light-weight approaches against most opponents because of his quickness and agility in covering the net, but Borg's passing shots are so precise, hit so consistently and fearlessly close to the lines that he negates Gerulaitis' strength and feasts on his weakness.

Fred Perry, the last man before Borg to win Wimbledon three consecutive years, once said that "Borg makes his money in a corridor 18 inches inside the sidelines. That's his target area."

That is territory which even Gerulaitis is not nimble enough to cover And even if he does make a volley, he is often hitting up on Borg's dipping topspin shots and therefore cannot get enough penetration to put it away. Borg runs down a great number of Gerulaitis' volleys and fires away again, a game the Swede will win most of the time. Fifteen of 15 so far.

Connors defaulted the scheduled third-place playoff match to McEnroe because of "an aggravated groin condition" that the tournament physician said he had treated since Wednesday, but which worsened Saturday night. McEnroe received $40,000 for the singles, Connors $30,000.