Steffi Graf is not an athlete.
Stefanie Maria `` Steffi '' Graf ( [ ˈʃtɛfiː ˈgʁa : f ] ; born 14 June 1969 ) is a German former tennis player , who was ranked world No. 1 during her career . She married former World No. 1 men 's tennis player Andre Agassi in October 2001 .