24. Monica Seles
When Seles won the French Open in 1990, she was just 16-years old. However, she packed a mighty powerful left-handed serve. Not to mention her two-handed backhand, complete with her traditional grunt. Seles won eight more Grand Slam titles — eight total while she was still a teenager. Seles, who won nearly $15 million in her career, even managed to win her fourth Australian Open three years after her infamous 1993 on-court stabbing incident.
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