Childhood must seem long ago and far away to Tracy Austin. Two years ago, when she won the U.S. Open, she was 18 and seemingly immune to stresses and strains of adulthood.

Now she is 20 and her body refuses to let her go on. For almost two years, she has struggled to play with injuries: a sore shoulder, a sore sciatic nerve, a stress fracture of a rib, all on her right side, all interconnected. Today, she made the adult decision. She withdrew from the Open and announced she will not compete again until November.

"I've had enough playing just to be playing," she said.

Austin, who is still ranked fourth, has not won a tournament since the Wells Fargo Open last summer. This spring, she lost to Martina Navratilova in the final of the Family Circle Cup, the only final she has reached this year. She has not finished a tournament since she lost in the French Open. She defaulted during the second set of the semifinal match against Wendy Turnbull at Eastbourne in England.

She went to Wimbledon and withdrew before her first match, just as she did today at the suggestion of her coach, Tony Roche. She said she will go with him to Australia, work out, and rejoin the tour there in November.

"For the last year and a half, I've played at 60-70 percent of my potential," she said. "It makes it frustrating to go out there. I'm virtually a perfectionist."

Austin said there has been "a lot of pressure to come back too quick from various people" but declined to say who was pressuring her. Sometimes the most vicious pressures are the internal ones. It is hard to accept the limitations of a body that knew none for so long. She says she is stopping now so "I'm not doing this vicious cycle" of "patchups."

Others wonder about her future, whether she has a future. She says, "I'm only 20, I'll be back . . . I'm going to take the time off and get strong. Do it right."

The cruel pressures of this elegant game were visible on the court as well. Chip Hooper, who looks so strong, who looks like such an athlete, was forced to retire from his match with Fritz Buehning at 2-0 in the fifth set because of cramps in his left leg. After coming from behind to win the third set tie breaker, Hooper hobbled through the fourth set. He tried to volley but he could barely make it to the net. Finally at break point against him in the second game, he lunged for a forehand volley and collapsed at the net. He hoisted himself ever so slowly to his feet, shook Buehning's hand and limped off. Buehning will now play Vitas Gerulaitis, whom he beat in the first round last year.