11. Martina Navratilova
The Czech star is the oldest female tennis player to win a major. She achieved this in 2006 when she remarkably won the mixed doubles at the US Open at the age of 49. Some consider her the best female tennis player of all-time, although Serena Williams might have something to say about that.
She won more singles and doubles titles in the Open era than any other elite player. Although most of her victories came in the 1970s and 80s, she played well into her 40s. Navratilova’s rivalry with Chris Evert is the stuff of legend in tennis. She is the only player in history to have held the top spot in both singles and doubles for over 200 weeks.