6. Martina Hingis
Achievements as a Teen: Martina Hingis is one on the most accomplished teenage athletes of all time. She came within one match of completing the career Grand Slam at just 16 years old in 1997. She lost the French Open final to Iva Majoli that yearâ€”undoubtedly a trivia question for years to come. Hingis captured numerous singles and doubles titles, all before the age of 20.
Career Recap: Hingis hung up her racket with a record of 548-133. She claimed 45 titles and ascended to the number one ranking in 1997 at just 16. She won the Australian Open from 1997-99, Wimbledon and the US Open in 1997, and was a French Open finalist in 1997 and 1999. She has gained $20,130,657 in prize money alone, and is a 12-time Grand Slam finalist. She was recently inducted into the Hall of Fame earlier this year.