Martina Rival is a professional tennis player who has been competing since the early 2000s. Her main rival in the sport is Steffi Graf, a German tennis player who won 22 Grand Slam singles titles during her career. CHRIS Evert is another professional tennis player who was active in the same era as Martina Rival and Steffi Graf. She won 18 Grand Slam singles titles and was known for her powerful groundstrokes.