Sania Mirza quelled a late challenge from world number 49 and 11th seed Anne Keothavong to sail into the pre-quarter-finals of the US $220,000 WTA Aegon Classic in Birmingham on Wednesday.
The unseeded Indian beat the British No 1 6-1, 7-6(5) in the second round after battling it out for one hour and 27 minutes.
Sania next runs into the winner of the match between local wild card Elena Baltacha and Russian fifth seed Anastasia Pavlyuchenkova for a place in the quarter-finals.
Sania dominated the first set, breaking thrice, and did not give any chance to Anne.
However, Anne shrugged off the rustiness in the second set and put up a brave fight to stretch it to a tie-breaker, where Sania held her nerve and converted her second match point.
Sania had beaten Tatiana Poutchek in the first round on Tuesday night.