Hana Mandlikova called it "the worst tennis match of my life." Wendy Turnbull had her chances, but "threw them away."

Yesterday both women were upset in quarterfinal matches as the Virginia Slims tennis tournament lost its second- and third-seeded players.

The favorite, Martina Navratilova, exacted harsh revenge on Helena Sukova, one of only two women to beat Navratilova during the last 19 months. Sukova lost the first seven games of the match before some in the audience had found their seats.

"Anytime anybody beats me, I remember it for the rest of my life," said Navratilova after her 6-0, 6-4 win. "That's the biggest mistake she ever made."

Mandlikova, the tournament's defending champion and second seed, appeared to be playing in a coma yesterday in a 6-4, 6-2 loss to 17-year-old Kathy Rinaldi.

"Maybe she didn't play her best game, but that's the way it goes," said Rinaldi, who has won three upset matches at George Washington University's Smith Center, including a first-round victory against sixth-seeded Claudia Kohde-Kilsch. "I feel real good about it. I've never beaten her before."

Turnbull lost to Zina Garrison 6-2, 7-6 (7-4). Garrison and Turnbull are from opposite ends of the world, literally and figuratively. Garrison is 21, grew up in Houston's inner city and learned to play tennis in a public parks program. Turnbull, one of the oldest players on the tour at 32, grew up playing country club tennis in Queensland, Australia.

But yesterday they played like identical twins, both breaking the aggressive serve and volley pace periodically with delicate drop shots and seeing-eye lobs.

"Wendy's game is pretty much the way I want to get mine," said Garrison, who has now beaten Turnbull their last three meetings. Garrison had trouble scoring points on her serve, but very little trouble with Turnbull's.

"It's disappointing because I didn't take my chances," said Turnbull. "I had them and just threw them away."

Manuela Maleeva, the sad-faced Bulgarian teen-ager, justified her No. 4 seed yesterday by beating Kathy Jordan, 6-1, 6-4. Maleeva, a base line player who depends more on placement than power, allowed 25-year-old Jordan to dig herself a hole in the first set.

Jordan, who had been playing well in this tournament, the first since a foot injury forced her off the tour last October, got fewer than half her first serves in against Maleeva.

"My serve is the cornerstone of my game. When you don't have your strength going for you . . . . I was just struggling," said Jordan. Maleeva, meanwhile, couldn't miss. At one point in the eighth game of the second set, Maleeva hit a lunging backhand that hit the net, then seemed to crawl over it for a point.

"God is with her," muttered Jordan, who lost the game on the point.

Navratilova seemed to have luck on her side too. Net shots were falling fair, passing shots were skidding on the sideline tape. When Sukova finally won the second game of the second set, she smiled in relief.

"What else could I do? Everything I tried, she hit," said Sukova.

In today's semifinal matches, Garrison will play Navratilova and Maleeva will face Rinaldi. The first match should be all serve and volley, a style favored by both Garrison and Navratilova.

Last night Navratilova served notice, both on and off the court, that she is ready to begin a new victory string. Her last, a record for men or women, was stopped by Sukova at 74.

"So much hard work went down the drain with that loss," said Navratilova. "But I'm getting real comfortable and confident."

The Rinaldi-Maleeva semifinal will be a battle of base liners. Both resemble human backboards at their best and the match could last for hours.

"I'll get ready for that game tomorrow," said Rinaldi. "I want to enjoy this one for the rest of today."

Rinaldi has become one of the crowd favorites at this tournament. With her wild blond hair and a face that reddens a shade darker with each set, she looks like the tomboy who grew up to be a fashion model.

When she turned professional at the age of 14, she was hailed as the teen successor to Tracy Austin and Andrea Jaeger. She reinforced that hope the same year when she became the youngest player to win a match at Wimbledon and reach the quarterfinals of the French Open.

But as Rinaldi's rise in the ranks slowed during the next few years, the pundits looked elsewhere for a new teen phenom. And that bothered Rinaldi not a bit.

"Maybe people have expected me to reach the top real quickly. But maybe it's better to go slow," said Rinaldi. "And keep enjoying it." At George Washington University Smith Center Quarterfinals Singles

Kathy Rinaldi, Martin Downs, Fla., def. Hana Mandlikova, Czechoslovakia, 6-4, 6-2; Zina Garrison, Houston, def. Wendy Turnbull, Australia, 6-2, 7-6 (7-4); Manuela Maleeva, Bulgaria, def. Kathy Jordan, King of Prussia, Pa., 6-1, 6-4; Martina Navratilova, Fort Worth, def. Helena Sukova, Czechoslovakia, 6-0, 6-4. Doubles

Mandlikova-Turnbull def. Carling Bassett-Kim Shaefer, 6-2, 7-6 (7-5); Sukova-Claudia Kohde-Kilsch def. Camille Benjamin-Pam Casale, 6-0, 6-0. Today's Schedule

1 p.m.: Rinaldi vs. Maleeva; Sukova-Kohde-Kilsch vs. Mandlikova-Turnbull.

7 p.m.: Navratilova vs Garrison; Navratilova-Gigi Fernandez vs. Jordan-Elizabeth Smylie.