Sania Mirza 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 of Belarus and Sun Tiantian of China, both unseeded, advanced to the last eight stage.

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

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