India's Sania Mirza has waltzed into the semi-finals of the Doubles and the quarter-finals of the Singles category in the Women's Pattaya Open Tennis tournament, taking place 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.Meanwhile in the Singles event, unseeded Sania yesterday outplayed Anne Keothavong of England, 6-4, 7-5, to make it to the last eight stage. Sania will next play Su-Wei Hsieh of Chinese Taipie for a place in the semi-finals.