Serena Jameka Williams (born September 26, 1981) is an American professional tennis player. She has won 23 Grand Slam singles titles, the most by any player in the Open Era, and the second-most of all time behind Margaret Court (24). The Women's Tennis Association (WTA) ranked her singles world No. 1 on eight separate occasions between 2002 and 2017. On her sixth occasion, she held the ranking for 186 consecutive weeks, tying the record set by Steffi Graf. In total, she has been WTA No. 1 for 319 weeks, which ranks third since WTA Rankings began behind Graf and Martina Navratilova. She is the only American player, male or female, to win more than 20 majors.