Like so many accidents, it began with a routine so familiar its risks had been nearly forgotten. Twelve-year-old Bonnie Gadusek was poised on the lower of the uneven parallel bars, about to execute a "seat circle catch" to the high bar. A star pupil at the Eva Gymnastics Club in Pittsburgh, Pa., she had performed the exercise hundreds of times. But on that day, Feb. 13, 1976, as Bonnie swung her tiny body up and around the wooden bar, her hand suddenly slipped. While coach Eva Szabo looked on in horror, Gadusek plunged to the floor, breaking her neck.

Bonnie survived, but her dreams of becoming an international champion were shattered. "I'm sure Bonnie could have made it to the Olympics. She was so dedicated, so talented," says Szabo. Forbidden to return to gymnastics after the accident—another fall would almost surely have crippled her—Gadusek could have settled for a quiet life on the sidelines. Instead, she found a new sport at which to excel. "At first I was worried that tennis wouldn't be quick enough for me," says Bonnie, who turned pro 15 months ago at 18. "But the better I got at it, the more I liked it."

Today, only seven years after she first laid her hand on a racket, Gadusek is the world's 18th-ranked woman player. She won $112,150 in prize money in 1982, and made it to the quarter-finals of the U.S. Open before losing to tournament winner Chris Evert Lloyd. Last August she received the first annual Omega Award as the player who has triumphed over the greatest obstacles. Says Susan Adams, editor of World Tennis magazine, "No one else who's pushing the top 10 started as late as Bonnie. She's remarkable."

Bonnie's success story is an old-fashioned tale of faith and fortitude. Hospitalized after the accident, she lay in traction for three weeks. For the next six months she wore a heavy steel brace, which held her upper body totally rigid. Intensely uncomfortable, the traction exerted unrelenting pressure on her jaw, and eventually she lost most of her back teeth.

The psychological pain was still worse. Cut off from her friends at Eva's gym and at school—since she couldn't move her head to read, she had to be tutored at home—Bonnie became despondent. Then her sister Darlene gave her a $5 K mart tennis racket. "At first I didn't want to play with it," says Bonnie, who was able to walk and move her arms with the brace. "But since I didn't have anything else to do, I started going over to the backboard near my house where the neighborhood kids threw baseballs. I'd kick them off so I could use it."

Soon she was practicing constantly. "I'd make up imaginary games," she recalls. "I'd pretend I was at Wimbledon and the U.S. Open." Every day her tutor had to drag her away from the backboard. But the Gaduseks were more relieved than worried by Bonnie's obsession. Confides her mother, Sylvia, a nurse, "If it hadn't been for tennis, I think Bonnie would have had serious frustrations."

That summer Bonnie played tennis nonstop. Mrs. Gadusek took her to a local YMCA, where tennis coach Dutch Hoffman told Bonnie she could start lessons in two weeks. "No, I want to start now," she demanded. Moved by her determination, Hoffman led her outside to the courts. "Immediately I was impressed," he says. "Here was this scrawny kid strapped into this awful contraption. But I could see she had raw talent."

A month later Bonnie placed second in her first tournament, sponsored by Gimbels department store in Pittsburgh. "I didn't even know how to keep score," she says. "My sister had to sit on the sidelines and put up her fingers." But Evonne Goolagong Cawley, who was in town for World Team Tennis matches, was amazed. "How in the world did you play in that brace?" she asked as she presented Gadusek with a four-inch trophy. Bonnie smiled. "It wasn't easy," she said.

Nor were the next five years. As winter approached, the Gaduseks hunted for an indoor tennis club that would offer Bonnie free court time. Only one did—the Greentree Racquet Club—and it was a 45-minute drive from their home. Every day Bonnie's father, who died last winter, drove her to the club after school with a brown-bag dinner. At 8 p.m. her mother would pick her up on the way home from work.

In 1977 Bonnie was ranked 11th in the girls 14-and-under category by the Middle States Tennis Association, embracing Pennsylvania, southern New Jersey and Delaware. But she wasn't satisfied with her progress. "I wrote to 30 tennis coaches, saying I wanted to be a professional and asking for a scholarship," she says. Only Harry Hopman, the famous Australian coach who had moved to the U.S. in 1970, showed interest. Within a few months Bonnie and her parents had moved to a small house in Largo, Fla. to be near Hopman's tennis school. Sisters Darlene and Annette were both dancing professionally, and brother Frank was in college.

Hopman realized at once that Bonnie was no ordinary player. "There are a lot of motivated people, but not all of them dislike to lose the way Bonnie does," he has observed. Although Bonnie has never thrown a McEnroe-type tantrum on court, she sometimes cries by herself for hours after a loss. Says her first coach, Dutch Hoffman, "Bonnie is the world's worst loser. But that's all right. I used to tell her, 'A good loser is a loser.' "

Bonnie has always shown the single-mindedness demanded by excellence. Tennis has taken her to Rome, but she has never seen the Sistine Chapel; to Paris, but she has never been to Notre Dame or the Louvre. Says Bonnie, "I concentrate on winning my matches." Adds her mother, "Bonnie lives tennis. There's nothing else in her life."

Despite such dedication, tennis insiders are ambivalent in assessing her future. Says one, "I don't think Bonnie has the variety and ability to be on the very top." Bonnie disagrees. Her goal, she says, is to win the U.S. Open. She recently fulfilled another dream by buying a house in the fashionable Bardmoor area of Largo, where Andrea Jaeger lives.

Behind Gadusek, if not entirely forgotten, is the sport that once seemed her pathway to stardom. Long ago her mother threw out all her old ribbons and trophies and sold the carpeted balance beam her father had made. ("After the accident, I never walked on it again," says Bonnie.) Yet despite her tennis successes, the pain of that near-fatal fall lingers in her mind like a shadow. "Whenever a gymnast comes on the TV," says Mrs. Gadusek, "Bonnie walks out of the room."