By | September 09 2012 9:22 PM

In a difficult battle against the Belarusian Victoria Azarenka, the American Serena Williams came back Sunday to win her fourth U.S. Open women's singles title in a hotly contested three-set match -- 6-2, 2-6, 7-5 -- at Arthur Ashe Stadium in Flushing Meadows in New York.