When John McEnroe walked onto the stadium court at the U.S. Tennis Center this afternoon, his mood was sanguine. It was a warm, breezy afternoon and, as is always the case here in the early rounds, a restless crowd was wandering in and out of the stadium looking for some excitement.

"I felt as good coming in here as I've ever felt," McEnroe said. "I just couldn't believe how flat I was out there."

He was out there for 3 hours and 50 minutes and, before he finally raised his left hand in the air to salute himself, the crowd and the setting sun, he had been scared out of his wits by Israel's Shlomo Glickstein, the 175th-ranked player in the world.

McEnroe finally won, 6-1, 6-7 (3-7), 2-6, 6-3, 7-6 (9-7), sending the afternoon crowd of 21,008 home sated and exhausted after a first-round match that had the kind of emotional twists and turns usually reserved for the final weekend.

"The guy just played an unbelievable match," McEnroe said. "I mean, he played a hell of a match. Part of it might have been me, but part was definitely him. He was jerking me around, giving me trouble with his serve. I was in shock out there. When I went down two sets to one, I realized I could definitely lose the match."

Had he lost, McEnroe would have been the first defending champion beaten here in an opening round. As it was, his brush with elimination was easily the highlight of an otherwise routine first day in which eight men's seeds and eight women's seeds all advanced.

Among the men, third-seeded Mats Wilander, sixth-seeded Anders Jarryd, No. 8 Boris Becker, No. 10 Joakim Nystrom, No. 12 Johan Kriek; No. 13 Tim Mayotte, and No. 16 Tomas Smid, were all straight-set winners. On the women's side, No. 3 Hana Mandlikova and No. 5 Claudia Kohde-Kilsch led the advance into the second round.

None had to work as hard or as long as No. 1, McEnroe. None walked off the court and said with a deep sigh, "I've never been so happy to win a first-round match in my life."

Two years ago, McEnroe had to go five sets to get through the first round here against Trey Waltke. But in that match he didn't go up a break twice in the final set and botch the lead; he didn't have to serve twice to stay in the match; he didn't have to play a last-set tie breaker, and he didn't blow four match points before finally surviving.

"On the big points he was more aggressive," said Glickstein, who once beat Ivan Lendl in the first round of a tournament in Stockholm. "When he needed a point, he came up with a big shot. He played those points like a champion."

This did not start out as a day when McEnroe would have to dig deep to pull out a dramatic victory. He reeled off the first five games of the match and when Glickstein finally won a game, the tiny crowd in the stadium -- most people were on outside courts at that point -- gave him a rousing mock cheer.

But the tenor changed in the second set. The tie breaker and Glickstein's victory began to bring fans pouring into the stadium. McEnroe was out of sorts. He bickered briefly with one fan but for the most part kept his temper under control.

Glickstein dominated the third set, breaking McEnroe twice. By now, as the sun began dropping toward the western rim of the stadium, most of the seats were filled by a crowd that clearly was divided.

"I think for a while the crowd helped him quite a bit," McEnroe said. "But at the end, I think it helped me too because it gave me adrenaline. I don't know what it was, but I felt weak or something out there."

For his part, Glickstein, who is 27 years old and has been ranked as high as No. 33 in the world, remained impassive even as he came closer and closer to what would have been the most stunning moment of his career. In 1980, Glickstein became the first Israeli to win a match at Wimbledon, beating Raul Ramirez. He has reached the quarterfinals of the Australian Open.

But this -- this would have been history. Yet Glickstein never showed the emotion of the moment. He just kept running down balls, kept McEnroe off balance and kept placidly walking back to the base line after each point, win or lose. At 6 feet 2, 195 pounds, he hardly looks quick, but he kept getting to balls McEnroe thought were winners.

"I wanted to make sure I got his serve into play, at least make him volley on every point," Glickstein said. "I didn't want to give him any free points. The strategy worked almost 100 percent."

Almost. After McEnroe broke early in the fourth set, he evened the match almost routinely. When he broke Glickstein in the third game of the last set, it looked as if Glickstein's moment had passed.

"By then, I knew I was in a really tough match," McEnroe said. "I was just fighting my butt off to win, get out and regroup."

McEnroe even resorted to looking toward the corner where his longtime coach, Tony Palafox, sat one row in front of McEnroe's parents and girfriend, Tatum O'Neal. Palafox kept giving hand signals as if trying to help McEnroe solve the riddle.

Up that early break, McEnroe couldn't finish off Glickstein. Glickstein broke back to tie the set at 3-3 when McEnroe netted a forehand after a spectacular rally. McEnroe broke back. Glickstein returned the favor -- at love.

Glickstein quickly held to lead, 5-4, and when he slammed a backhand return at McEnroe's feet, it was 15-30. McEnroe was two points from defeat. McEnroe paused, searched the cloudy sky, took a deep breath and came up with three straight serves when he had to have them. Two were winners, one an ace.

Five-all. McEnroe let out a breath as if he felt he had come back to life. Each man then held serve easily and they went to the tie breaker.

"I certainly had the chance then," Glickstein said. "But he played good points. I felt he won, more than I lost."

McEnroe quickly led, 3-1, but Glickstein rallied to 3-3.

McEnroe rolled his eyes again and played three superb points to lead, 6-3. Three match points. Finally, he had Glickstein reeling. Wrong.

McEnroe got a first serve in. Glickstein never blinked and drove a backhand at McEnroe's feet. McEnroe scooped the volley into the net. McEnroe served again. This time, Glickstein landed a lob just inside the line and McEnroe netted a forehand. That was two match points thwarted. Glickstein served, McEnroe netted the serve. Three match points. It was 6-6.

As Glickstein prepared to serve, someone broke the silence with a yell. Glickstein stopped his toss. A moment later, McEnroe whipped a backhand return past him. Did the yell hurt?

"I don't know," Glickstein said. "I had just saved three match points, I was concentrating and then . . . "

Still, Glickstein proceeded to save a fourth match point with yet another wonderful backhand return. McEnroe, looking glazed by now, finally twisted a serve for a winner and an 8-7 lead. One more time, Glickstein served. McEnroe crushed a backhand crosscourt. Gamely, Glickstein ran the ball down one more time. But his backhand clicked into the net.

"You have to give the guy credit," McEnroe said. "He just hit shots I didn't think he could hit. I really thought I had things together coming in here, but that's down the tubes now. I'm just glad to get out of this match . . . I know I won't take anything for granted after this."