Azarenka dropped the first set on a tie-break – 0-7 – before coming back strongly in the second and third to win through 6-7 (7-0) 6-0 6-2.
The Belarussian hit plenty of unforced errors in the opening set, but, once she began finding her lines, began hitting consistent winners, outscoring her opponent on that statistic by 39 to 16.
Azarenka was simply the more accomplished of the two players, and she judged her approaches to perfection today, winning 21 of 26 points at the net, no mean feat on a hardcourt. She will face holding Champion Kim Clijsters in what is set to be an enthralling Semi-Final.