Nadal beats Delbonis, reaches semis in Argentina Open
Maria Sharapova withdraws because of stomach virus
Azarenka, champion in Doha in 2012 and 2013, won 2-6, 6-2, 6-4.
The world No. 2 beat the 18-year-old 6-2, 6-1 in 56 minutes.
The unseeded American topped Dr. Ivo in two tiebreakers.
Pioneers Billie Jean King, Gladys Heldman, and the rest of the Houston 9 laid the groundwork for the WTA.
It's hard to imagine a clearer clash than this net-rusher vs. baseliner battle.
Four years after a setback, 34-year-old Venus Williams continues to turn back the clock.
The best may be yet to come for eight-time major champ Novak Djokovic.