Japan's top female player Ai Sugiyama has plummeted from No. 29 to No. 49 in the WTA tour's new world singles rankings, which were updated Monday after the conclusion of the Australian Open.
Sugiyama, whose singles form has taken a nosedive over the past year, kept her world No. 1 rankings in doubles after a healthy string of results, including success at the U.S. Open women's doubles title last year in tandem with Frenchwoman Julie Halard-Decugis.
Switzerland's Martina Hingis retained her world No. 1 singles ranking, despite losing in the final of the Australian Open to resurgent American Jennifer Capriati on Saturday.