Chris Evert

The American baseliner who never lost a Grand Slam final -- going 18 for 18 in Grand Slam finals she reached, before losing her 19th -- Chris Evert won 18 Grand Slam singles titles and maintained a career win-loss record of 1,309-146 (89.96%), the highest winning percentage in professional tennis history. Her rivalry with Martina Navratilova across 80 matches over 16 years is considered the greatest rivalry in sports history by many commentators.