The Russian eased to victory in the first set without even facing a break point, but could she could not maintain that momentum as she was broken twice to surrender the second.
The deciding set was a far tighter affair with both players tested to the limit, but it was the world number two who prevailed to claim a 6-3 2-6 7-5 victory.
Sharapova told wtatennis.com: "She plays pretty well off both sides, the forehand and backhand, but I think she does much better when she has the time to create angles or change directions, just like any other player.
"I lost momentum in the second set because I wasn't being as aggressive or stepping in as much, just not having as much on my ball as I did in the first set.
"I'm really happy with the way I fought through it in the third. I'm really happy I was able to come through in this match."
Sharapova will be faced in the final by Li Na, who beat American Bethanie Mattek-Sands in straight sets.
The second seed from China broke the qualifier's serve almost at will, doing so on five out of 10 occasions in a routine 6-4 6-3 triumph.
Mattek-Sands, who remarkably had been forced to save a match point against Maryna Zanevska in the second qualifying round, had beaten Yanina Wickmayer, Sara Errani and Sabine Lisicki in the main draw but her dream run came to an abrupt end.