LONDON, JUNE 30 -- Pam Shriver walked off the court this afternoon, looked around her, waved to some friends and fell flat on her back. She lay there, arms outstretched, for a full minute, partly because she was savoring the moment, partly because she was dead tired.

If ever a match could be labeled "The Perils of Pamela," this was it. Twice, Shriver, seeded No. 5, was down a match point to Sylvia Hanika, the No. 16 seed. Twice, she came up with sharp volleys. It took her 2 hours 33 minutes, under a warm midday sun, but when it was over, Shriver had one of her most gratifying victories, surviving by 6-7 (7-4), 7-5, 10-8.

"I got a good tan out there," she joked. "Actually, I can't remember the last time I won a match from match points down. Fortunately, for once, when it really got tight, I came up with some good stuff. That was the difference in the match. I was just a little less tight at the end."

Shriver was down a set and in trouble at 5-all in the second. She saved that set and then promptly went down, 4-1, in the third. She broke back to 4-3, and lost her serve to go down, 5-3. She came back to 5-all, faced the match points at 5-6, was down 0-30 at 6-7, down 0-30 again at 7-8 and finally pulled the match out with two wonderful games at the finish.

"I served well the whole match," Shriver said. "I only served two bad games all day. But she's really playing well and I hadn't played a left-hander in so long that it was tough for me. She just kept me off-balance all day."

Hanika, 27, was a finalist in the French Open six years ago and was ranked in the top 10. But a series of injuries slowed her for several years and only recently has she broken back into the top 20. These days, Steffi Graf is all the rage of women's tennis in West Germany, so almost no one notices Hanika at home.

But at 5 feet 8 and 145 pounds, Hanika is dangerous, particularly when playing serve and volley on grass. Nonetheless, once Shriver had gotten the first break of the match to win the second set, she seemed in control, especially when Hanika double-faulted twice to go down, 15-40, in the first game of the third set.

But Shriver played two sloppy returns that Hanika pounced on and, when Shriver lost the game, she promptly played a loose second game on her serve to go down, 2-0. From that point, it was all uphill for Shriver.

"I kept telling myself that I wasn't playing badly, that she was really serving well, but that if I hung in I could pull it out. You don't expect an easy match in the round of 16 at Wimbledon, but that one was a little too tough for my taste," Shriver, who is from Lutherville, Md., said.

Shriver has tried very hard to have what she calls "a quiet tournament." She had three easy rounds but today ran smack into the kind of match that often gives her trouble: a hot player on an outside court, where the combination of noise and tension are often more than she can bear.

"But I didn't panic," she said. "I was really happy during that match that I had been good during April and May with my training. If I hadn't done that, I don't think I would have gotten through it."

Having survived Hanika, she now faces a hot player, Helena Sukova, in the quarterfinals. Sukova, who beat Martina Navratilova and Chris Evert at Eastbourne two weeks ago, routed a good player, Raffaella Reggi, 6-0, 6-0, today. Three weeks ago, Reggi beat Sukova in the French Open.

"I came into the locker room and I asked Helena her score and she told me love and love," Shriver said. "I told her, to be fair, she better have a damn long doubles match."

Sukova is, like Shriver, tall (6-2) and a power player. She will be a tough hurdle to clear. But Shriver isn't intimidated. "I've said all along that I want to be very quiet here until it's time to make a big splash.

"Helena is very tough, but that's a small splash. I'm talking about a really big splash, I mean a cannonball off the high board. If I beat Helena, that's a step toward the big splash."