In set two, Azarenka broke serve early to reach 2-1 before the set remained on serve with Azarenka still holding the lead at 4-2.
However with Williams striking a mix of aces and powerful groundstrokes, the American took three games in a row to reach 5-4.
With Azarenka serving to stay in the set at 30-40, a controversial out call on an Azarenka down the line inside out forehand which Williams said distracted her led to the point to be replayed after a conversation between the two players and the chair umpire.
Williams then struck a forehand down the line winner to break serve and level the match at one set all.
After the set point in anger, Azarenka struck a ball into the stands for which she received a code violation warning for ball abuse. And although Williams had used some colorful language before taking set two, it was not said loud enough for the the chair umpire to hear which had resulted in no violation called on the muscular American.
Azarenka broke serve after Williams double faulted on break point then held serve to lead 2-0 in the final set.
Williams however then raised the level of play game again as she took the next five games with aces and aggressive crosscourt baseline winners which kept Azarenka on the run.
With Azarenka serving to stay in the match, Williams struck a forehand down the line return winner which she followed up with a crosscourt forehand passing shot winner to reach 15-40.
On her first match point, the American produced a stunning crosscourt forehand passing shot winner to break serve and end the match after winning the last six games of the set.