There are only three players these days in the high-stakes game of King-of-the-Hill in men's tennis: Bjorn Borg, Guillermo Vilas and Jimmy Connors. That is the tennis triangle - not eternal, but for the time being. Perhaps we should call the No. 1 man "the Grand Hypotenuse."

"Did this tournament decide who is the best player in the world? Connors was asked shortly after his 6-4. 1-6, 6-4, victory over Borg Sunday in the final of the $400,000 Colgate Masters Tournament at Madison Square Garden.

"I knew that would be the first question," he snapped, somewhat testily. "Well, beat me, Borg beat Vilas, and I beat Borg, so let's paly it all over again."

Undoubtedly they will. Often. For the Masters reaffirmed what had become obvious throughout the 1977 season: Borg. Vilas and Connors inhabit a plateau a shade above all the other fine players on the landscape.

The Masters was the final playoff for the top eight finishers in the 1977 Colgate Grand Prix point standings, but it was also a triangular meet, a three-cornered showdown. One British journalist suggested. "There were really three world-class players here, and then the other five." That was a trifle harsh. Actually, there were five world class players, and three in a stratospheric superclass.

The "other five" were Brian Gottfried, Manuel Orantes, Eddie Dibbs, Raul Ramirez and Roscoe Tanner. Outstanding players all, but it is difficult to imagine them climbing up to the Borg-Vilas-Connors elevation in the coming year or two.

If there is a fellow likely to share the penthouse suite, and flamboyant enough to fit in, it is Vitas Gerulaitis, who recently won the Australian Open on fast grass to go along with the Italian Open title he took last May on slow clay. His five-set masterpiece against Borg in the Wimbledon semifinals burns bright in memory as the best match of the centenary Wimbledon.

But that is another story. The issue of the morent, following the last tango in New York, is the world rankings for the season.

There is no official list, just as there is no definitive final ranking of college football teams. But as nearly all the pools selected Notre Dame tennis experts are virtually unanimous in declaring Borg "the Grand Hypotenuse."

It does not take a Pythagorean Theorem to figure this out.

The 21-year-old Swede won the most important tournament, Wimbledon, beating Connors in the final. He didn't play the Australian Open, French Open, or World Championship of Tennis (WCT), and defaulted to Dick Stockton in the fourth round of the U.S. Open because of a bad shoulder. At the Masters, he beat Vilas in the semis and lost to Connors in the final.

Borg had the best winning percentage of the year: .920, on 81 victories and seven issues, counting four-man round-robin tournaments but excluding one-set World Team Tennis results. He won 13 of the 20 tournaments he played. More important, he was 3-0 head to head against Vilas and 2-1 against Connors.

Vilas was runner-up in the Australian won the French and U.S. opens (beating Gottfried and Connors in the finals), and had an astounding streak the last six months of 1977, losing only one match the rest of the calendar year after being upset by Billy Martin in the third round at Wimbledon.

Vilas steadfastly refused to consider the Masters part of the 1977 season, preferring to imagine that his rivals turned into pumpkins at midnight on Dec. 31, but he and coach-manager Ion Tiriac were alone in that view. As Connors said Sunday, "winning the Masters is a great way to start 1978, but the tournament really belongs mor to 1977."

Rankings must reflect a full year's results.Vilas won an impressive 21 of 34 tournaments, compiling a .909 winning percentage on a 140-14 record, including four-man events and Davis Cup play. But he cannot erase his 0-3 record against Borg.

Connors - No. 1 in 1974 and 1976, and No. 2 to Arthur Ashe in 1975 - won eight of 21 tournaments and amassed a 70-11 record (.864 winning percentage). He won the WCT Finals at Dallas and the Masters, and was runner-up at Wimbledon and Forest Hills. But he was 0-2 against Vilas (including their all-time classic in the round-robin portion of the Masters) and 1-2 against Borg.

All superb records, but the head-to-head rivalries within the triangle must be the determining factor this time.

Rankings will always be subjective. Computerized lists are only as good as the programs on which they are based. The U.S. Tennis Association released a set of world rankings last week that were simply ludicrous. Its computer somehow perceived Vilas as No. 4, and was therefore greeted with the derision it deserved.

The Lorge Rankings might also be ridiculed in some quarters, but be forwarned that they will be defended with bear-like tenacity. The 1977 world rankings as I see them:

MEN: 1) Bjorn Borg, 2) Guillerino Vilas, 3) Jimmy Connors, 4) Vitas Gerulaitis, 5) Brian Gottfried, 6) Manuel Orantes, 7) Eddie Dibbs, 8) Dick Stockton, 9) Roscoe Tanner, 10) Raul Ramirez.

WOMEN: 1) Chris Evert, 2) Virginia Wade, 3) Billie Jean King, 4) Martha Navratilova, 5) Betty Stove, 6) Sue Barker, 7) Wendy Turnbull, 8) Rosemary Casals, 9) Dianne Fromholtz, and 10) tie: Jausovec/Kerry Reid.

Growl.