Jennifer Capriati at US Open

Jennifer Capriati made her professional debut in 1990 at the age of 13 years, 11 months, finishing that first season as the world No. 8. She had several firsts this year: youngest player to reach a tour final, youngest player to reach the semifinals of the French Open, the youngest seed at Wimbledon, and youngest player to qualify for the season-ending championships. She was named WTA Newcomer of the Year in 1990 and reached the semifinals of two majors the following year, including the 1991 US Open, shown here. The WTA rules that now bar players younger than 15 from playing on the tour are called the “Jennifer Capriati Rules.”