The only time Greg Holmes had seen Guillermo Vilas play was on television. The only time Holmes had been in the stadium at the National Tennis Center was as a spectator. "It was like when I sat there in the stands, the court looked so small," he said. "I wondered how you can even hit a ball in it. So I decided not to look up."

Today, Holmes confronted Vilas in the flesh in the third round of the U.S. Open and found him mortal. Holmes, the 1983 NCAA champion who was wild-carded into the tournament, beat Vilas, the sixth seed, 6-2, 6-2, 6-3, in what was surely one of the worst losses of Vilas' career.

"Some guys look different on TV," Holmes said. "He looked the same."

And definitely not larger than life. Still, he had decided not to look up.

After four days of tranquility, there was tumult at the U.S. Open. Jimmy Connors, the defending champion, easily defeated Bruce Manson despite a threat made on his life. A caller reported the threat to U.S. Tennis Association officials at 1:15 this afternoon, according to USTA spokesman Ed Fabricus. According to Fabricus, the caller, who declined to identify himself, said he had heard "on the street there would be a threat on Jimmy Connors' life today."

Connors was informed of the call before his match by John Smith, director of men's professional tennis for the USTA. "He said, 'I'm going to play,' " Smith said.

USTA officials declined to desscribe security precautions, but Connors was whisked to a limousine immediately after the match.

In more mundane developments, Andrea Temesvari, the No. 9 women's seed, was upset by Pascale Paradis, the French and Wimbledon junior champion, 6-4, 6-0. John Lloyd, husband of Chris Evert, took another step toward reasserting his own identity by beating Terry Moor, 6-3, 5-7, 2-6, 6-0, 6-1.

Lloyd, who won the mixed doubles title at Wimbledon this year with Wendy Turnbull, had never gotten to the final 16 in singles in a Grand Slam event before. "It gave me a lot of my self-respect back, even though it was mixed doubles," he said.

As he left the court with his wife today, she said, "You go first, you're the star now."

Martina Navratilova, the No. 1 women's seed who appears to be on cruise control, had another easy day in the sun, beating Kate Gompert, 6-2, 6-2. But Andrea Jaeger, the No. 3 seed, barely survived her eighth encounter with Mima Jausovec, 6-2, 6-7 (2-7), 7-6 (7-1).

Jaeger led, 5-2, in the second but lost that advantage as Jausovec succeeded in pressuring her by rushing the net. After breaking in the 11th game of the final set, Jausovec served for the match. At 30-30, Jaeger hit a forehand return down the line that was called good, then overuled by umpire Paul Molloy. That gave Jausovec her first match point. But Jaeger's next return, a cross-court forehand, caught Jausovec midcourt as she tried to attack and she netted the half volley.

Twice Jaeger claimed the advantage and lost it, as Jausovec abandoned her serve-and-volley tactics to rally from the base line. On the 11th point of the game, a backhand error wide gave Jausovec another match point. This time she netted a backhand. Two more backhand errors gave Jaeger a reprieve. She took a 4-0 lead in the tie breaker as Jausovec began to cramp and finally to fold.

Mentally, you have to finish a match. I didn't and she didn't," Jaeger said. "She gave me a second chance and I'm not going to blow it."

Vilas wasn't close enough to blow it: he was simply blown away. Holmes, who turned 20 Monday, never gave Vilas a chance. Time and again, he anticipated Vilas' looping topspin ground strokes and came in, taking them early and putting them away. His two-handed backhand was fierce. His unorthodox two-handed forehand, which he learned when he was 4 years old and not strong enough to lift the racket with one hand, is a potent shot now.

Holmes was unyielding. "He took the short looping shots and cracked balls to the corner," said Steve Stefanki, the coach of the U.S. Pan American team. Holmes won a gold medal in the recently concluded Games in Caracas, Venezuela.

Concentration is obviously a problem for Vilas, who had 30 unforced errors. He is appealing his suspension by the Men's International Professional Tennis Council, which said he accepted $60,000 in appearance money to play at a tournament. "It has been hurting my game for a long time," he said.

He tried changing tactics, lobbing more. Holmes, tired and and a bit nervous, served for the match at 5-1 and had a match point but was broken, missing all but one of his first serves. But Vilas must have known it was almost over in the next game when Holmes stood his ground at the net, deflecting one, two, three passing shots. Finally, he put away a lunging forehand volley and fell to the ground. "I was beat," Holmes said.

Vilas held, barely, saving three match points, and Holmes tried again. Success.

Holmes, who is ranked 453rd, says he has not decided whether to return to school at Utah, where he plays No. 1, or turn pro. He has decided to take off six months and play the Asian circuit. He says he went to Utah because he was offered a full scholarship and "I like to ski."

Stefanki said Holmes was the only one of the U.S. players who didn't complain about the conditions at the Pan American Games. "Two of them complained about preparing for the U.S. Open," Stefanki said. "I said, 'This is perfect preparation. The crowds hate you and the conditions are hard. You'll come to the Open and it will be a breeze.' "

Today, it was.