Last year, when Pam Shriver beat Martina Navratilova in the quarterfinals of the U.S. Open, she put her arm around her friend and said she was sorry. Today, when Shriver, the fifth seed, beat Andrea Jaeger, the third seed, 7-6 (7-2), 6-3, in the quarterfinals of the Open, to force a semifinal confrontation with Navratilova, she stopped on her way to the locker room and spoke to Jaeger's father. "Sorry," she said.

"You see the father a half-hour after the match, what are you going to say?" she asked, shrugging, pausing. "People usually don't say sorry to me. I'm sympathetic to losers. Whenever I shake hands with someone, I try to express sympathy. Not sorry that I won, sorry they had to lose, I guess that's the way I wish I'd be treated."

Shriver was as gracious after the match as she was graceful during it, in her gawky, gangly way. Her size has always been the source of her game, and the expectations that attend it. Big. Today, she played big. Her serve was big when she needed it to be and she showed a large amount of patience. On the big points, she waited for the right moment to come in behind her slicing backhand approach shots and made the volleys count.

She was also the bigger player. Jaeger, who is ranked third in the world, was disgruntled and distracted throughout the match by line calls and let those dominate her play. At 5-5 in the first set on Shriver's second serve, Jaeger thought the ball was long, played it, won the point and complained anyway. Finally, exasperated, Shriver told her pointedly, "Play the . . . calls."

Jaeger's response was impolitic. At the end of the match, she waved her racket handle at umpire Joan Vormbaum and said, "I hope you know that you just cost me that match."

"She was obviously a big factor," Jaeger said later. "One time I asked her if she was allowed to be removed--I didn't say can you be removed, I just asked--she said, 'Yes, if you think I'm incompetent I can be removed.' She was putting words in my mouth and I knew there was no way now if anything happened and the ball was four feet inside the line I sure wouldn't get it . . . It was hard to psych myself up because I was getting more involved with the calls than with my game, which shouldn't happen."

Everyone else conformed to expectation. Navratilova, who has not lost a set in five matches that have taken a total of 246 minutes, beat Sylvia Hanika with consummate ease, 6-0, 6-3. Ivan Lendl, the No. 2 seed who has not lost a set in four matches, and only 22 games thus far, beat Johan Kriek, 6-2, 6-4, 6-1. Mats Wilander, the No. 5 seed, easily defeated Andres Gomez, 6-2, 6-1, 6-2.

The oppressive heat on the stadium court gave Lendl more trouble than Kriek did. Lendl is as expansive as he was once dour. He seems relaxed on and off the court. "I'm hitting more and more difficult shots every time I go out there," he said. "I like it. Why not?"

Aaron Krickstein, a 16-year-old sensation, was beaten by Yannick Noah, 6-3, 7-6 (7-2), 6-3. Noah, the fourth seed, refused to give him the pace or openings that Vitas Gerulaitis did. "Somebody like Gerulaitis or (Jimmy) Arias hits the ball solid on their ground strokes and you can get into a better groove," Krickstein said. "He hits a lot of chips and spins and it was a little windy and tough to get into a groove."

Though he always seemed to be on the verge of being overpowered by Noah's repertoire and solid first serve, Krickstein was in the match until 2-1 in the second set tie breaker. Krickstein served a second serve and lobbed over Noah, who had come in on the third exchange of the point. Noah backpedaled, thinking he might have an overhead, and reconsidered, realizing the impossibility of the shot.

Then he did something more impossible. He whirled, ran to the baseline and hit a forehand crosscourt through his legs. Krickstein, stunned at the net, slapped at it, a high forehand volley down the line. Noah lunged and hit a forehand crosscourt winner that Krickstein unwisely allowed to drop in the corner. It was the kind of point that ends a match in the middle of it. Krickstein, who says he will probably turn pro in the near future, lost the next three points and any momentum he might have had.

Smiling ruefully, Noah said he practiced the shot "just for fun. If you are playing five hours a day and it becomes boring, you try it. Before you try it, make sure you have something to cover, because it's kind of dangerous."

Krickstein said, "I knew my lob was going in but I sort of lost the ball because I didn't know what he was going to do with it. Then when he it I didn't know if it was going out because it was with the wind and I hit it pretty high and then the next ball I thought was going wide and was way in."

Arias, the ninth seed, advanced to the quarterfinals, after falling behind, two sets to one, to Joachim Nystrom, of Sweden, 3-6, 6-3, 3-6, 6-0, 6-0. Then he got an idea. "At first I was just pouring one cup of water over my head," he said. "I thought I would have to default. I asked the ball girl for 10 cups of water. I just took a shower in it. Then I felt great."

In the fifth set, Arias held at love in the first game, broke at love in the second, and held at love in the third, as his potent forehand and the heat depleted Nystrom.

It was 93 degrees and oppressively humid, which may have accounted for Jaeger's overheated performance. At 5-5, after the pointed exchange of words, Shriver fell behind, 15-40, saved two break points, the second with an ace, and thrust her fist in the air. She had two set points against Jaeger in the next game but Jaeger saved them with backhand and forehand passing shots.

Jaeger immediately fell behind, 0-3, in the tie breaker on several close calls, the third a doublefault. She never seemed to recover her composure. Shriver finished off the tie breaker with a lovely forehand lob and then a forehand drop volley. She started off the second set by breaking on the sixth game point with a forehand deep in the corner that Jaeger hit long. "After my first break in the second set, I honestly did not go all out on her service games because I felt I was serving well. It turns out to be a good strategy."

Shriver was tested once, saving two break points at 4-3. "Two atrocious backhand volleys," she said. "I got three points to get out of it. I think it took the last little bit out of her."

Jaeger's problem is composure, not concentration. A couple of weeks ago, in a tournament in Los Angeles, she got into a shoving match with Renee Blount after a doubles match because she felt Blount's grunting sounded like out calls. Incidents like that have prompted some people to wonder whether she wants to be playing tennis.