Claim: In 2011, Monica Seles won her last Grand Slam singles title while she was a citizen of the USA.

Monica Seles -LRB- -LSB- ˈsɛləs -RSB- Szeles Mónika , Моника Селеш , Monika Seleš , -LSB- ˈsɛlɛʃ -RSB- , born December 2 , 1973 -RRB- is a former Yugoslav world no. 1 professional tennis player and a member of the International Tennis Hall of Fame . An ethnic Hungarian , she was born and raised in Novi Sad , SFR Yugoslavia . She became a naturalized American citizen in 1994 and also received Hungarian citizenship in June 2007 . She won nine Grand Slam singles titles , eight of them while a citizen of Yugoslavia and the final as a citizen of the United States of America . In 1990 , Seles became the youngest-ever French Open champion at the age of 16 . She went on to win eight Grand Slam singles titles before her 20th birthday and was the year-end world no. 1 in 1991 and 1992 . However , on April 30 , 1993 , she was the victim of an on-court attack , when a man stabbed her in the back with a 9 in long knife ; Seles did not return to tennis for over two years . Though she enjoyed some success after rejoining the tour in 1995 , including a fourth Australian Open title in 1996 , she was unable to consistently reproduce her best form . She played her last professional match at the 2003 French Open , but did not officially retire until February 2008 .   Regarded by many in the sport as one of the greatest tennis players of all time , Seles was named one of the `` 30 Legends of Women 's Tennis : Past , Present and Future '' by Time .