Indian tennis ace Sania Mirza was unhappy with her performance in the opening round doubles match at the USD 1,75,000 WTA Sunfeast Open in Kolkata on Wednesday.

"I am not happy with my performance, because I did a lot of mistakes," Sania said at the post-match media meet after she partnered South African Liezel Huber to victory against the Indian pair of Ragini Vimal and Archana Venkatram.

Asked whether the problem was with her forehand, Sania replied, "No. Actually my service was not good."

Sania said that she would have to improve on this aspect in her singles second round encounter against German Sandra Klosel on Thursday.

Asked to comment on her partner Huber, she said "We are playing together for sometime. We know each other's game quite well."

On how they plan to prepare for the challenges ahead, Sania said "We are looking forward step by step."

The Hyderabad girl said the tag of top seed has not put them under any additional pressure. "When we play we don't think about seedings. We only concentrate on the match."

On the controversial decision given by the chair umpire in today's doubles match, Huber said "It is the umpire's fault. She has not given the decision rightly."

"But it is neither mine nor Sania's responsibility to point out the mistake to the umpire. We are only concerned about our game," she said.