She was the dominant player in the women 's game during 1991 and 1992 , but in 1993 , she was forced out of the sport for two years following an on-court attack in which a spectator stabbed her in the back with a knife . She was the World No. 1 player in the women 's game during 1991 and 1992 , but in 1993 she was forced out of the sport for more than two years following an on-court attack in which a man stabbed her in the back with a 9-inch-long knife .