Serena Williams competes in women's singles and doubles.
Serena Williams . The Women 's Tennis Association ( WTA ) has ranked her world no. 1 in singles on eight occasions , from 2002 to 2017 . Her record of 39 Grand Slam titles puts her third on the all-time list and second in the open era : 23 in singles , 14 in women 's doubles , and 2 in mixed doubles .