Steffi Graf’s father, a car-insurance salesman from Brühl, Germany, taught her how to swing a racket in their living room when she turned 3. She never stopped. Although Martina Navratilova and Chris Evert hit the ball hard, Graf brought new explosiveness to the game: her forehand remains one of the greatest shots in women’s tennis. She contested 31 Grand Slam singles finals and won 22 of them (with at least four titles at each Grand Slam tournament). In 1988 she completed the calendar-year Grand Slam by winning all four majors, and walked away at age 19 with an Olympic gold medal to boot. An enigmatic champion, she let her racket do the talking, and remains mysterious as a result. Reflecting on her career, Graf, 42, tells TIME, “Although the achievement of all four Grand Slam titles and an Olympic gold medal in 1988 stands out as my greatest accomplishment in tennis, my life with the family and watching the kids grow gives me greater joy than my tennis achievements.”