Somehow, the ending seemed wrong. Even to John McEnroe. In his moment of victory today, as Bjorn Borg's final backhand sailed long to give McEnroe his third straight U.S. Open tennis championship, McEnroe stood still for a moment as if unsure what to do.

Finally, he punched his fist through the air and turned to shake Borg's hand. "I didn't know what to do exactly," McEnroe said. "I think, I guess, I was a little confused."

McEnroe's 4-6, 6-2, 6-4, 6-3 victory over Borg today, a romp given the nature of this rivalry, ended amidst a swirl of questions, most surrounding a second death threat made against Borg, his lightning-fast disappearance from the grounds, his absence at the awards ceremony and his refusal to answer any questions about the match.

But one answer stood out clearly when night fell on the National Tennis Center: at this moment, John Patrick McEnroe is the best tennis player in the world.

Never was his ascendency more evident than today. For 2 1/2 sets the two men were even. But midway through the third set, McEnroe moved in and began pummeling Borg with every kind of shot imaginable, leaving the Swede dazed, disheartened and confused.

"He played a great first set but then for some reason he seemed to let up," McEnroe said. "I was really surprised by the way he tried to play today. He didn't seem to know what he wanted to do a lot. He didn't play his game today."

The reason apparently was not the death threat, the second received by phone here against Borg in as many days. This one came at 4:45 p.m. after the match had already started and Borg was not told of it.

When the match ended, a coterie of security guards surrounded him. According to officials, Borg told the security men, "Go (to) the locker room," as soon as they arrived at his side. He was escorted from the stadium immediately, not staying for the trophy presentations or to accept his $33,000 runner-up check.

From the stadium, Borg went to the locker room, which was sealed off while he showered. Then he was taken out a back door to a waiting station wagon. As he left, Borg refused to answer questions of several reporters trailing him.

There was no indication from Borg, his coach Lennart Bergelin or the USTA that Borg's quick exit was connected to the death threat.

The confused finale distracted attention from McEnroe, who was dominant today when he had to be in becoming the first player since Jimmy Connors (1974) to win both Wimbledon and the U.S. Open in the same year. He is the first player since Bill Tilden (1920-1925) to win three straight U.S. titles.

"I played my best match of the tournament by far, but that's not surprising," McEnroe said. "It's not that hard to play well against him because the adrenaline is flowing, and you know you're going to be mentally ready and psyched up."

Early, Borg was the one who looked ready, trying to end his frustrations in this tournament now stretching over 10 years, including four losses in the final in the last six years.

He broke McEnroe at love in the seventh game of the match and easily served out the set, the first time he had won the first set of a final here.

But McEnroe broke Borg quickly in the second game of the second set, running around a backhand on break point to hit an inside-out forehand down the line for a clean winner.

He broke again to lead 5-1, hitting the exact same shot on break point off another Borg second serve. Borg got that one back when McEnroe played a careless game and lost his serve a third time, double-faulting on set point.

The crowd, 18,804 on a warm, breezy late afternoon/evening, settled back, expecting another epic. Instead, they saw McEnroe play two sets of remarkable tennis.

Briefly, though, Borg still had the fire. He broke McEnroe in the fifth game of the set, hitting two excellent returns to get to break point, then watching in delight as McEnroe butchered an easy forehand volley. Each man then held serve and Borg served, leading 4-3.

Until that point, the match had lacked the usual Borg-McEnroe fury.

But in that eighth game, McEnroe put together four shots as memorable as have been seen in a major final in a long time.

He started with a crackling crosscourt backhand that Borg didn't even move for -- love-15. Briefly, McEnroe was human, pushing a forehand long -- 15-all. Borg came up with a hard serve and came in. McEnroe got to the first volley and uncorked a perfect forehand topspin lob. Again, Borg could only watch -- 15-30. Borg came in behind another serve. McEnroe ran right, stopped and hit a textbook crosscourt backhand passing shot -- 15-40.

Now, he completed this masterpiece game. Another Borg first serve, again the Swede came to net, punching a hard volley towards the corner. McEnroe ran the ball down and , with a flick of his wrist, hit another ungettable, untouchable topspin lob over the nonplussed Borg's head.

McEnroe had the break back and Borg's shoulders slumped noticeably as he walked towards his chair for the change. McEnroe was in control, the attacker, the chaser; Borg was just trying to survive.

McEnroe won the third set by breaking Borg in the 10th game after Borg saved two set points. On the third, McEnroe angled a forehand return so wide that Borg's weak return merely set up an easy crosscourt winner for the set.

In the fourth set, McEnroe broke at 15 to reach 3-1, again ending the game with a clean winner. "I tried to tell myself then not to think I had the match won," McEnroe said.

But he played sloppy enough the next game to give the break right back to Borg. But it merely postponed the inevitable. Borg played a horrid game serving at 2-3. He started by netting a volley and hitting a forehand long and ended by pushing two easy backhands over the baseline.

"That game was really important to me," McEnroe said. "The crowd was starting to really get going for him and if he had won the game he might have gotten going, too."

Borg saved two match points serving at 2-5, but McEnroe served out the match in the next game, finishing with two big serves, the last one punched long by Borg.

"The game I played to break back in the third was probably the most important," McEnroe said. "That's one of the best games I've played on someone else's serve in a long time. After that game I felt like I could make almost any shot, I was at least willing to attempt them, go for things. When you feel like you can make shots, you take chances."

Today, as he has done the last three times they have played in major finals -- here last year and Wimbledon this year prior to this match -- McEnroe took the chances and converted them.

McEnroe's $66,000 first prize today is incidental to his winning of a fourth major title, to his evening his record at 7-7 with Borg and to his third straight major victory over the Swede, three years his senior.

Tonight, McEnroe has firmly established himself as the No. 1 player in the game. Time for celebration?

"Maybe for a little bit," he said. "But not for that long. You have to go on."