Justine Henin

The Belgian one-handed backhand technician who retired twice (in 2008 and 2011) despite being ranked world number one, Justine Henin won 7 Grand Slam singles titles and was never beaten by a seeded opponent at Roland Garros during her peak, going 61-6 at the French Open. Her backhand was considered the most technically perfect shot in women's tennis history by analysts, and she defeated Serena Williams in four of their seven Grand Slam meetings.