The youngest female player to reach world No. 1 in singles is Martina Hingis of Switzerland. Hingis achieved this feat on March 31, 1997, at the age of 16 years and 6 months. She held the top ranking for a total of 209 weeks during her career and won a total of 5 Grand Slam singles titles. Hingis was known for her exceptional court vision, her ability to anticipate her opponents' shots, and her outstanding doubles skills. She was also a successful doubles player, winning a total of 13 Grand Slam doubles titles and 7 Grand Slam mixed doubles titles.