Ten days into the new year, Bjorn Borg and Jimmy Connors produced a tennis match for all seasons in the $400,000 Colgate Grand Prix Masters Tournament, a scintillating slugfest of the sort that in 1977 and 1978 distinguished their rivalry as one of the greatest in the sport's history.

Borg wound up winning this torrid battle tonight, 3-6, 6-3, 7-6, to extend the mastery that he established in 1979 over his longtime arch-rival to seven straight matches. But Connors fought back furiously from 2-5 down in a magnificent 74-minute final set and fought off two match points in the decisive tie breaker, which Borg won by 7 points to 4.

This was tennis and drama of the highest order, its fierce intensity and shifting fortunes more than making up for a few patches of ragged play.

In the end, it was marked by the quality that has set the best Borg-Connors confrontations above all others of the modern era in tennis. The combativeness was palpable, the sustained pace and boldness of the shotmaking extraordinary. Each man made spectacular shots in turn, and ultimately every point became a war.

As the tide swung from Connors to Borg to Connors and eventually back to the glacial Swede, the vocal crowd of 16,753 at Madison Square Garden took to screaming on every point, creating an electric atmosphere.

Connors, slimmed down to 152 pounds and eager to make up for a disappointing 1979, displayed all his old internal combustion, and it spilled over into outbursts of obscene gestures and ranting at a line umpire. Connors' grosser moments heightened the passions of the crowd, and some took to yelling during points or just before the players served.

There were three other matches on the second of three days of round-robin play in this final playoff for the top eight singles players and top four doubles teams in the 1979 Colgate Grand Prix of tournaments around the globe.

John McEnroe was the complete master of spin, touch and angle in carving up Guillermo Vilas, 6-2, 6-3, despite falling over the net, bumping his head and briefly raising fears he was injured seriously.

Vitas Gerulaitis, despite tiring in the second set because he has had flu, knocked Harold Solomon out of contention for Saturday's semifinals, 6-1, 7-6. Roscoe Tanner likewise bumped Jose Higueras from the running, 7-5, 6-4.

This left Borg and McEnroe, who seem destined for a showdown here for the No. 1 world ranking for 1979, virtually assured of semifinal berths with 2-0 records.

Connors, Vilas, Gerulaitis and Tanner are still alive with 1-1 records going into Friday's matches: Solomon against Vilas, Connors against Tanner, Borg against Higueras and McEnroe against Guerlaitis in a rematch of the U.S. Open final.

But everything else that happened today -- including McEnroe's extraordinary touch and athleticism at the net in searing Vilas, and his Humpty Dumpty tumble over the net as he lunged for a net-cord dribbler while serving for the match -- paled in comparison to the Borg-Connors epic.

Borg last year thumped Connors from the status of grand rival to personal whipping boy, beating him in all six meetings. In the first four, on four different surfaces (clay in Florida, cement in Las Vegas, grass at Wimbledon, indoor carpet in Tokyo), Connors could not win more than three games in any set.

But Borg, the four-time French Open and Wimbledon champion, sensed that Connors was lean and hungry to avenge a professionally disappointing year in which he did not get beyond the semifinals of any major tournament and fell to No. 3 in the world for the first time since 1973, behind Borg and McEnroe.

"Last year, everytime, I was playing very well against Jimmy," Borg said beforehand, "but this year I think he is very, very eager to come back and win a big tournament, because he didn't win one last year, and show he can still win big titles.

"I think the match will be more like we used to have, with long rallies . . . a very tough match."

He could not have been more correct. After the 2-hour 38-minute gem was finished, Borg said it was one of their most dramatic struggles, perhaps second only to the 1977 Wimbledon final that he won after Connors resurrected himself from 0-4 to 4-4 in the fifth set.

Certainly this match was in a class with the stirring 1976 U.S. Open final and the 1978 Masters final, both won by Connors before admiring crowds in the Big Apple, where he plays best. Only this time Borg, who has never won a tournament in New York in 12 tries, was victorious. Just barely. "I was beginning to wonder why I can never play my best tennis in New York," he admitted after blowing his 5-2 lead in the torturous final set.

Borg started well, holding easily in his first two service games, shoving Connors to break point twice in the second game and once in the fourth.

It looked then as if the match might fall into the recent Borg-Connors pattern, Connors pouring all his energy into an early assault only to find Borg trumping his best shots and then surging to victory as Connors deflated like a hurricane blowing itself out.

But instead it was Connors who broke serve first, in the fifth game. He used a tactic that has been employed frequently against him, suddenly and unexpected taking pace off the ball in rallies to induce Borg to over-hit.

Surprisingly, Borg started missing his first serves, and, uncharacteristic, unforced errors crept into his game. He made four bad ground-stroke errors, hit an easy overhead wide, and double-faulted in losing his serve again to end the first set.

By then, Connors was playing more like his old self than at any time in 1979. He was pounding his ground strokes savagely . . . lunging for slashing volleys at full stretch, almost horizontal to the court . . . uncoiling into shots with both feet off the ground, producing an incomparably physical brand of tennis . . . strutting and swaggering, making crude curses and gestures . . . leaping 18 inches off the ground for smashes struck with animalistic fury and his own, inimitable, primal grunt.

But Borg, so calm and totally undemonstrative by contrast, was simply better -- virtually unassailable from the back court, able to win some easy points on his serve for a breather, and equipped with a much greater margin of safety in the rallies because his topspin shots clear the net with a higher arc than Connors' flatter, riskier strokes.

Connors lost his serve twice to fall 0-3 in the second set, and his behavior became aroused, too, as Connors ranted at officials.

Meanwhile the points became more and more compelling. Both players made astonishing "gets," diving volleys, remarkable shots off of uncompromising rallies.

At one stage, the crowd erupted in appreciative applause when Borg got to a drop volley, swift as the wind, and held the ball on his racket long enough to see which way Connors was moving at the net before scooping a forehand winner down the line to the corner. Moments later, they gasped as Connors cut off a seemingly perfect passing shot with a ferocious backhand volley.

Connors held his serve only twice in the second set, and when he fell behind 2-5 in the final set it seemed as if his wrath and frustration might well over into angry surrender. But instead he kept hammering, and it was the usually unflappable Borg who tightened and grew tentative.

"I didn't serve as well in those last games, from 5-2," Borg said, "and I got a little bit scared because I hit too many short ones. That's exactly what Jimmy likes. He comes in on them."

Borg was also down 0-30 and two advantage points when he served at 5-all.

At that critical juncture, Borg reasserted his nerve. He whaled a mighty forehand down the line which Connors astoundingly chased down, but lobbed just long on the dead run. Advantage Borg, and he delivered a clean ace -- his fourth, to counteract six double-faults -- down the center.

Connors, who had hit an incredible forehand down-the-line pass at full sprint in holding for 5-5, was still pumped up, though. He held from 30-30 to force the tie breaker, winning the last point with another flying backhand volley, launched with an involuntary, leonine gurgle from deep inside him.

But Borg served another ace on the first point of the tie breaker, and Connors sailed a backhand approach long and sprayed a diving forehand volley after saving himself with two extraordinary "gets," including a volley from the back court that was improvised from sheer athletic instinct and insatiable hunger to reach the ball.

Borg got to 6-2, but Connors made his last stand, saving two match points with a backhand drop volley and a slashing forehand cross-court volley. He had one serve left, but steered a forehand down the line wide off a backhand return that skipped off the net cord.

"When it comes to the tie breaker, you need a lot of luck," the stolid Borg said. "Anything can happen. You must have a good start, and I had a very good start."