The way Zina Garrison was looking at it, if your back is so close to the wall that you can feel the cement through your shirt, there isn't much sense in being cautious. So, already down a set yesterday and staring at one match point and then another, Garrison unleashed two rockets, generically known as serves.

"Those were the two best serves she hit all match," said Terry Phelps, who came within a point of beating the world's eighth-ranked player in their second-round match in the Virginia Slims of Washington. Instead, Garrison climbed back in and went on to win, 2-6, 7-6 (9-7), 6-4.

Martina Navratilova had the sniffles, but the way she is playing now, it didn't really matter. The world's top player made just three unforced errors in beating Pam Casale, 6-0, 6-2, in 45 minutes last night and unless she loses to the world's No. 241, Susan Sloane, in the second round, she will be Garrison's opponent in the quarterfinals, which will start Friday.

Second-seeded Pam Shriver had a fairly easy time with Tina Mochizuki, winning, 6-2, 6-0, in about an hour. She next will face seventh-seeded Bonnie Gadusek in the quarterfinals.

"I thought if I was going to go down, I'd go down hitting," said Garrison after her match at George Washington University's Smith Center. "When you're down to match point, you kind of loosen up, because you might lose anyway. When it's do or die, sometimes you come out and sometimes you don't.

"It's kind of strange," she said of her serve that saved her. "I've been working on it and I felt I could hit it. But it was a matter of relaxing when I needed to hit one. And I really needed those points, and it came naturally."

Phelps, ranked 29th in the world, played a superb first set and had Garrison on the ropes.

"For a while there, I didn't think I was going to come out of that," said Garrison. "Terry was hitting unbelievably in the beginning, and there was nothing I could do. Thank God, I came out of it."

What got Garrison going -- and none too soon -- was what she perceived as a bad call. With Phelps up 5-2 in the second set, Garrison was serving at deuce. Her first serve was down the middle and was called out.

"No, way! That wasn't out," was her exclamation to the chair umpire. She chatted for a moment, got nowhere and went back to serve with a bit more fire in her eyes. "That's when I got upset," she said later. "After that I started hitting the ball and winning a lot of points."

She held serve, then broke Phelps to get to 5-4. Phelps was up 30-40 when the first of Garrison's good serves caused Phelps to hit a backhand wide. On the second match point, Garrison responded with an ace, and then won to reach 5-5.

In the third set, Garrison broke Phelps to go up 4-2. But Phelps didn't quit, though the end was near. She made a rare appearance at the net to break Garrison and win the seventh game, and then held serve to tie. But Garrison turned up the heat for one more burst and won the last two games to advance to the quarterfinals, where she will likely face Martina Navratilova.

Garrison is 23, lives in Houston where she grew up, and has been among the top dozen players for most of the past three years. She thinks she's past the point where people recognize her more for being black than for being talented.

"I think that because I've been between sixth and eighth for so long that I think people just say 'Zina's a good player,' " Garrison said. "Naturally, they're going to say Zina's the top black player because I am black."

And she enjoys being a role model.

"Actually, I look at it as a positive thing," she said. "There's not that many blacks in tennis, and by doing your best, maybe you can help someone else in a minority situation see that they can do it, too. I do enjoy (being a role model). My one goal is to be a higher role model, so when you say something, people will listen."

Slowly, more blacks are coming into tennis. The 32 players in the main draw here included three blacks, though that percentage is not necessarily a norm.

"I've gotten exposure, and blacks, generally, have been exposed to it more and they are better able (than they used to be) to afford it," Garrison said. "There are a lot more in the middle class and a little above, so they can afford to belong to clubs and where there is tennis."

Garrison is uncertain as to what extent more blacks will continue take up the sport.

"It will continue, but I don't know how far," she said. "There's another step that we, as a race, have to take, and that's to realize what you are and why you're that way. I see it a lot in tennis. People start to do well and lose sight of what they're all about, though I guess that's basically everybody."

Garrison is something of an anomaly, in that she received most of her instruction in the public parks of Houston.

"Ever since I picked up a racket, I've played there," Garrison said, though she added she also has been working at an indoor club in Houston. "It was a 15-minute bus ride to the park, which was in a nice neighborhood. The bus came right by my house and stopped right in front of the park. I played there from about 10 1/2 until I was about 18."

Garrison said she is really just starting to grow up, in terms of being independent and responsible for all her needs, such as buying groceries and doing laundry. And partially because of that, she doesn't know if being the No. 1 player is something she wants.

"It's a matter of if I want to be No. 1," she said when asked if she could. "I could get to be No. 1; that would be no problem. It's more a question of if I can handle all the things it takes to be that. I want to find myself and understand what I'm all about."

Three other seeded players advanced in yesterday's morning session. No. 8 seed Kathy Rinaldi beat Dianne Balestrat, 4-6, 6-2, 6-0, to advance to the second round, in which she will play Bettina Bunge. Gadusek advanced to play Shriver by defeating Anne White, 6-4, 5-7, 6-2. No. 4 seed Manuela Maleeva defeated Jo Durie, 7-5, 6-1. Sloane defeated Peanut Louie, 7-5, 6-2, in a first-round match.

Shriver, against Mochizuki, again served well and scored at the net as she had done Tuesday night in her first-round win over Sylvia Hanika.

Navratilova credited her victim, Casale, No. 34 on the computer, with playing "pretty well" and not making many unforced errors.

For Casale, the highlight occurred about 20 minutes into the match when she managed to hold serve and tie the second set at 1-1. Realizing she was hopelessly outclassed, Casale sarcastically encouraged the applauding crowd by waving her arms a bit.

"I forced the action, coming in on my serve and her serve," Navratilova said. "I had only three unforced errors and I'm happy about that."