Stefanie Maria "Steffi" Graf (born 14 June 1969) is a German former tennis player, who was ranked world No. 1 during her career. Graf won 22 Grand Slam singles titles. Her 22 singles titles puts her second on the list of Major wins by a tennis player (male or female) since the introduction of the Open Era in 1968 and is third all-time behind Margaret Court (24) and Serena Williams (23). In 1988, she became the first and only tennis player (male or female) to achieve the Golden Slam by winning all four Grand Slam singles titles and the Olympic gold medal in the same calendar year. Furthermore, she is the only tennis player to have won each Grand Slam event at least four times.