Serina Williams Wins her 15th Grand Slam TitlePosted on September 9, 2012September 9, 2012 Picture Credit: Usatoday.com Serina Williams has continued to dominate this summer and bit in three sets No. 1 Victoria Azarenka today (9/9/12) in the U.S. Open final 6-2, 2-6, 7-5. Williams won her fourth grand slam trophy in New York and 15th overall.