Top seed Vera Zvonareva withstood a strong second-set challenge from Austrian left-hander Sybille Bammer to advance to the semi-finals of the Pattaya tennis Open, winning 6-0, 7-6 (7-5).
Kazakh Sesil Karatantcheva reached her first career semi-final, taking three hours 23 minutes to overcome Russia's Ekaterina Bychkova 7-5, 4-6, 7-5 in a match that included a massive 41 break points.
She now plays Thailand's Tamarine Tanasugarn, who defeated Russian Anna Chakvetadze 6-1, 6-4 to reach the Pattaya semi-finals for only the third time in 17 attempts.
Zvonareva will face fourth seeded Kazakh Yaroslava Shvedova, who defeated Germany's Tatjana Malek 7-6 (7-4), 6-1.
