
Steffi Graf winning her first pro tournament at 16, 1986
This was against Chris Evert-Lloyd, a 18 times Grand Slam winner, at the WTA Hilton Head Island 1986.
In 1988 she won World Athlete of the Year after completing her historic Golden Slam by winning all four Grand Slam titles and Olympic gold in the same calendar year, which no athlete has ever been able to achieve since.*
* Serena Williams, Rafael Nadal, Andre Agassi (her husband) and Novak Djokovic have achieved a Golden Slam over the course of their careers, but not all in the same year.