Serena Williams is an athlete.
Serena Jameka Williams ( born September 26 , 1981 ) is an American professional tennis player . In total , she has been world no. 1 for 319 weeks , which ranks her third in the Open Era among female tennis players . She is the only tennis player in history ( man or woman ) to have won singles titles at least six times in three of the four Grand Slam tournaments , and the only player ever to have won two of the four Grand Slams seven times each ( seven Wimbledon titles and seven Australian Open titles ) . The arrival of the Williams sisters has been credited with ushering in a new era of power and athleticism on the women 's professional tennis tour . The WTA Finals ( formerly known as the WTA Tour Championships short : WTA Championships ) , is a professional tennis tournament played annually at the end of the season for the top-ranked players on the Women 's Tennis Association ( WTA ) tour .