The day before the Wimbledon men's singles final, when practically everybody from the bookmakers to the beefeaters at the Tower of London was predicting that Bjorn Borg would lop off Roscoe Tanner's head swiftly with strokes as cutting as the Lord High Executioner's ax, John McEnroe foresaw a match rather than a bloodletting.

"I think the Tanner has togot a good chance because he serves and gets to the net. Borg doesn't like begin put on the defensive on his return of serve," said McEnroe, the 20-year-old from Douglaston, N.Y. who had been expected to play Borg in the final.

"Borg loves playing Jimmy Connors because Connors stays back, and he can just get into the point. No one is going to beat Borg once he gets into the point, it's as simple as that. You've got to attack him a lot, and Tanner is at least going to try that. He might lose, but He's going to loss trying -- going for winners, attacking his second serves and getting in."

That, of course, is exactly how Tanner played Borg Saturday afternoon -- going for winner, attacking his second servies and going in right to the end of a scintillating match that Borg just barely won, 6-7, 6-1, 3-6, 6-3, 6-4. In five sets in 2 hours 49 minutes, Tanner lost his serve four times, Borg only once. And at the end the difference between them was about as thin as one of the fingernails by which the four-time champ was hanging.

McEnroe proved to be a reliable pundit -- not surprisingly, because he is the only player with a recent record of success against Borg. In five meetings over the past year, McEnroe has won three and had eight match points in a fourth. In May, he beat Borg for the World Championship Tennis (WCT) title in Dallas.

McEnroe's best weapon against the Swede -- one he foresaw Tanner using effectively as well -- is a superb left-handed serve of varied spin, pace and placement. McEnroe and Tanner can both serve flat slice or twist deliveries to any part of the court, but are best at the most natural of lefty serves: a slice wide and low to a right-hander's backhand.

That is the serve that gives Borg the most trouble -- particularly on fast, low-bouncing surfaces such as grass -- because it tails away from the slightly limited reach of his two-fisted backhand.

Even if he returns the ball, he is jerked out of position and moving the wrong away, leaving the court open for an easy volley. In Stockholm last November, when McEnroe played Borg for the first time on a fast and skiddy linoleum court, Borg was able to win only seven points in two sets on McEnroe's serve and lost for the first time in his life to a player younger than he was.

McEnroe was asked Friday how else to attack Borg, other than with the serve. But before he could answer, his partner Peter Fleming -- together they won the Wimbledon men's doubles and confirmed that they are the best pair in the world right now -- interrupted.

"You can get him at the changeover," Fleming wisecracked, effectively ending the conversation.

Ultimately, that might be the only way to beat Borg at Wimbledon: bash him over the head with a racket during a change of ends. Tanner hit him with almost everything else, playing the match of his life, but wound up wh ith only the satisfaction of coming ever-so-close to beating a man who had been deemed invincible for the most prestigious prize in tennis.

Asked 15 minutes after the match how he felt, Tanner said: "I've just finished, and I don't really think it's dawned on me. I might feel worse tomorrow because then I'll start thinking about it and start remembering the chances I had to win . . . But it certainly feels a lot better than getting beat the way I was by him the last time I was wwhere (1976 semifinals), in three straight sets, because I know I bothered him. My strategy presented him a few problems."

Indeed, Tanner had the champion scared. Borg kept repeating after the match how "scared" he had been how tight his legs felt. He said nerves made him gorget to move his feet on some points in the tense fifth set, and made him resort to safe spin serves instead of gambling boomers.

"I feel much, much older than when I went on the court," said the man who has won more major titles than anyone else ever did by the age of 23. "Especially in the end of the match, I've never been so nervous in my whole life . . . . I almost couldn't hold my racket, I was so nervous."

Even when it was over, and he received the gold champion's cup from the Duke of Kent for the fourth year running, Borg had butterflies in his tummy: "i didn't hear what he said because I was so happy. I couldn't believe I won. I just remember I was so nervous."

But even when his legs momentarily locked and his brain clouded, Borg's instincts and will to win took over. At the most eritical times he made the right plays, and never lost self-control. "Maybe that's why I have been so successful in tennis," he mused later, "because I can control myself."

"I think in the beginning I was a little bit unlucky with all the important points," he said, perhaps remembering the windblown lob that had won the first set tie breaker for tanner.

"He was serving very well, and it was very difficult to break him. But then in the fourth and fifth sets, I won all the important points -- every single one . . . . I think maybe He" Borg added, nodding to the heavens, "was on my side."

Surely Borg has made the most of his God-given talent. He has won 28 consecutive matches at Wimbledon, becoming the first man since New Zealander Tony Wilding in 1910-13 to win the singles four years in succession. Next year he could break Rod Laver's record of 31 consecutive victories -- set in 1961-62, when Laver was an amateur, and 1968-69-70, when he returned as a pro.

"In 1976, when I won Wimbledon for the time, I never dreamed to win it four times in a row," said Borg, who has also won the French open -- the premier clay court tournament -- four times, plus two Italian Opens, the WCT Championship, and the Davis Cup for good measure. "This is the beggest thrill of my life, because no one won four times in a row in modern history."

Already established as one of the all-time greats, Borg now has his sights on the U.S. Open. He was runner-up to Connors in 1976 and 1978, but hasn't won it. "I will play the Davis Cup, then rest and work very hard to prepare myself 100 percent," he vowed. If he wins at Flushing Meadows, N.Y., in September, he will go to Australia at the end of the year to try to complete the grand Slam previously accomplished only by Don Budge (1938) and Laver (1962 and '69).

The greatest obstacle to these ambitions will likely be McEnroe rather than Connors, who made another graceless exit after Borg humilated him in the semifinals.

We have probably seen the last of Borg vs. Connors as a great rivalry, for borg's superiority is now indisputable. He has met Connors three times this year -- on clay in Florida, on cement in Las Vegas, and on grass at Wimbledon -- and Connors has yet to get more than three games in any set.

Borg's game, especially his serve, has improved markedly since they were the grandest and most evenly matched of rivals to years ago. Meanwhile, Connors has, if anything, deteriorated. As Tanner said, "borg is very comfortable playing against Jimmy now, and Jimmy won't or can't change his type of game."

McEnroe has the style to challenge Borg. He can do all the things that Tanner did to trouble him, most of them better. He may be the most gifted of current players in terms of racket control and athleticism. He probably already has relegated Connors to No. 3 on the totem pole, but whether he is Borg's equal in the mind and heart remains to be seen.

Arthur Ashe, among others, has predicted that McEnroe will be the No. 1 player in the world within two years. But Borg is unquestionably the best right now, and since he has decided that he might like to be known some day as the greatest player who even lived, he could be tougher than even to dislodge.