India's Sania Mirza has waltzed into the semi-finals of the Doubles in the Women's Pattaya Open Tennis tournament in Thailand. In the Doubles quarterfinals yesterday, Sania and her Aussie partner Anastasia Rodionova defeated the Thai pair of Varunya Wongteanchai and Varatchaya Wongteanchai in straight sets, 6-4, 6-3. The Indo-Aussie combine, which has been given a top billing in this tournament, will face the third seeded duo of Japanese Kimiko Date-Krumm and her partner from Uzbekistan Akgul Amanmuradova in the semi-finals.In the quarterfinal of the singles event however, unseeded Sania was defeated by Su-Wei Hsieh of Chinese Taipie . Su-Wei Hsieh won in the straight sets 7-5, 6-3.