Sania Mirza [ Images ] overcame a tough challenge from Hana Sromova of the Czech Republic to move into the quarter-finals of the US $145,000 Tashkent Open women's tennis on Thursday.

Third seeded Sania made light of a delayed start due to rain to defeat Sromova 6-4, 7-5 in the second round.

In the morning, before the play was suspended, Victoria Azarenka [ Images ] of Belarus and Sun Tiantian of China, both unseeded, advanced to the last eight stage.

Azarenka defeated qualifier Dominika Cibulkova [ Images ] of Slovakia 6-4, 6-4 in an hour and 36 minutes. Cibulkova had knocked out No 7 seed Galina Vosboeva of Russia [ Images ] in the first round.

Sun eliminated Tatiana Poutchek of Belarus, also 6-4, 6-4.