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 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-inch (23 cm) long knife. Seles did not return to tennis for over two years. Though she enjoyed some success after rejoining the tour in 1995, including victory at the 1996 Australian Open, she was unable to consistently produce her best form. She played her last professional match at the 2003 French Open, but did not officially retire until February 2008.