The unseeded Indo-American combine humbled the top seeds 6-3 6-3 in just 69 minutes as Sania sounded a warning for the rivals ahead of the Australian Open.
It was fifth WTA title for Sania and Bethanie together.
Sania and Bethanie saved seven break chances in each set and broke their rivals five times -- twice in the opening set. They dropped serve once but kept the advantage of early break, which they got in the fourth game.
Sania and Bethanie then broke Raquel Kops-Jones in the next game to put pressure back on their opponents.
Sania had to pair with the American since her regular partner Su-Wei Hsieh was playing singles qualifiers at the Australian Open.
It is Sania's best performance at this event surpassing a previous quarterfinals appearance.
She and Bethanie earned 470 ranking points each and split USD 39,000 as prize money.
