Wimbledon champion Maria Sharapova was on course for her third straight WTA title on Saturday, beating fellow Russian Elena Dementieva in the semi-finals of the Zurich Challenge.

The 17-year-old world number seven from Siberia fought back from a set down to topple the world number five 4-6, 6-2, 6-3, and will take unseeded Australian Alicia Molik in the final, who beat local favourite and 10th-seed Patty Schnyder 4-6, 6-1 and 6-4.

"It was a very tough match and a very long one, so I'm happy to have won," Sharapova said after winning the match under two hours.

Winning her 12th victory in a row, Sharapova will seek her third straight title on the back of tournaments in Seoul and Tokyo.

Sharapova fired three aces in the opening game, but seemed to lose her concentration afterwards, awarding Dementieva the lead in the fifth with three unforced errors and a double fault.

Yet, she managed to turn the match around with a six-game winning streak at the end of the second and start of the third set.

Against Sharapova, 23-year-old Molik is considered an underdog,but the Olympic bronze medallist and world number 20 has already eliminated Russian sixth and eighth seeds Vera Zvonareva and Nadia Petrova in Zurich, before Saturday's three-setter against Schnyder.

The only previous meeting between Molik and Sharapova came at this year's grasscourt tournament in Birmingham, England, where the Russian won their quarter-final in straight sets.