"You've seen a lot of matches," George Austin said to a veteran observer of the U.S. Open tennis championships. "Were you excited by this one, or was it just me?"

No, Austin was assured, it wasn't only his pulse that was fluttering. Nearly everybody at the West Side Tennis Club has gotten excited about his 14-year-old daughter, Tracy, who today came back from 3-5 and two set points down in the second set to beat Virginia Ruzici, 6-3, 7-5, and move into the quarter-finals of America's premier tennis tournament.

Austin is taking a week off from his job as an aerodynamics engineers in Redondo Beach, Calif., to watch Tracy, thought to be the youngest player to compete at Forest Hills. "I've had enough sweaty palms," he said after her victory over Ruzici, a hard-hitting but erratic 22-year-old Romanian with a big topspin forehand.

But he will probably have more, Tracy - the 5-foot, 90-pounder who has become everyone's real-life Alice in Tennis Wonderland - has a good chance to beat Betty Stove, the 6-1, 160-pound Wimbledon runner-up and No. 5 seed, on Wednesday.

If she does, her semifinal opponent would probably be either Chris Evert, the 1975-1976 champ and No. 1 seed, who indulged Forest Hills in a similarly sentimental celebration of youth in 1971, or Billie Jean King, who ended Evert's dreamy debut that year in the semis.

King, who is playing singles at Forest Hills for the first time since 194, when she beat Evonne Goolagong in the last Open final before the surface was changed from grass to clay, reached the quarters today by beating Kerry Reid, 6-1, 3-6, 7-5. King broke when Reid served for the match at 6-5 in the third, then took the tie breaker, 7 points to 5.

Tennis has always been a family affair the Austins of Rolling Hills, Calif. - George, Jeanne, and their five children.

Tracy's older brothers, Jeff and John, played the doubles here, losing in the second round.John and Tracy hope to play the mixed oubles. Sisters Pam, the oldest of the brood, used to play the women's pro tour and is now a teaching pro. Brother Doug, the youngest of three sons, is a good local player.

But Tracy, who says she started playing tennis "as soon as I was old enough to pick up a racket with two hands," is the start of a remarkably well-adjusted and low-key family, where sibling togethersness was preached early as preferable to sibling rivalry.

John and Jeff have warmed up Tracy for 20 to 30 minutes before her matches here, and if they chafe at being referred to as "Tracy's brothers," they do not let on.

They are proud of the poise she has shown in beating Heidi Eisterlehner, Donna Ganz, No. 4 seed Sue Barker and Ruzici.

So is Bob Lansdorp, the Dutch-born Rolling Hills pro who has coached her since she was 6. "I would like to take a lot of credit, but I have to give most of it to Tracy," he said.

Unlike Ion Tiriac, who sits on courtside and gives signals to protege Guilermo Vilas after every point, or Dennis Ralston who sometimes passes mid matches note of encouragement to DIck Stockton. Lansdorp thinks the player should be independent on the court.

"When you try to give messages from the side, I think it's distracting," said Lansdorp. "Especially at this stage, when she has so much to learn. I'd rather see Tracy just go out there and gut it out. She learns more by working things out for herself than if I were constantly telling her what to do."

Tracy seems even younger than her 14 years, 9 months. She has braces on her teeth, says "ya know" about five times per sentence, wears her blonde hair in little girl bunches," and always goes on court in oversized pinaforces, handmade by her mother. (Today's was mint, with the word TENNIS embroidered on the yoke.)

But on court, she has composure and tactical sense far beyond her forehand grooved and started whomping it. Tracy found a variety of ways keep the ball away from it.

She used the pace that Ruzici gave her marvelously, and at just the right times threw in a shower of moonballs to take away the rhythm of the increasingly frustrated Romanian. Asked if Lansdorp had advised her on what strategic adjustments to make in various situations, she seemed astounded and said, "No, I just do it."

When Ruzici hit deep, or tried ot bounce big topspinning loopers overhead, Tracy stayed back and rallied patiently, occasionally climbing the back wall to retrieve shots high to her two-fisted backhand. When she got short balls, Austin displayed her naturally aggressive tendencies, moving in and putting away sure volleys.Both at the net and in the backcourt she has wonderful anticipation and gets quickly into position to make her shots.

She also got to practically every Ruzici drop shot, hitting forcing shots off them. Her explanation as to why she covers drops better than she did in losing to Evert in the second round at Wimbledon: "All the adults have tried to drop shot, hitting forcing shots off them. Her explanation as to why she covers drops better than she did in losing to Evert in the second round at Wimbledon: "All the adults havetried to drop shot me. I've gotten used to it now."