Premise: 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 . Graf was ranked world No. 1 by the Women 's Tennis Association ( WTA ) for a record 377 total weeks -- the longest period for which any player , male or female , has held the number-one ranking since the WTA and the Association of Tennis Professionals began issuing rankings . Graf reached thirteen consecutive Grand Slam singles finals , from the 1987 French Open through to the 1990 French Open , winning nine of them .
Hypothesis: Steffi Graf is an amateur tennis player.
Label: CONTRADICTION