September 2011 - Appointed a UNICEF international goodwill ambassador.
February 18, 2013 - At age 31, becomes the oldest female tennis player to be ranked number 1 since computer rankings began in 1975. This is the sixth time in her career to be ranked number one.
September 8, 2013 - Beats Victoria Azarenka to retain her U.S. Open title. At 31, Williams is the oldest female winner of the hard court Grand Slam in the Open era.