13. Tracy Austin
Achievements as a Teen: Tracy Austin won her first pro title at 14. No, that's not a typo. Two years later at 16, she captured the 1979 US Open singles title, becoming the youngest player to do so. In 1980 she became the youngest sports millionaire ever at the time. How does one top that, and all before they turn 18?
Career Recap: Austin finished with a career record of 335-90, racking up 30 titles along the way. She reached number one in the world in 1980 and was inducted into the International Tennis Hall of Fame in 1992. After that first historic US Open victory, she mustered one more championship in Queens in 1981.