Li Na to persevere with new serve

Li Na has vowed to persevere with her new service action despite her error-strewn defeat to Flavia Pennetta in the semi-finals of the BNP Paribas Open.

The Chinese number one, who is in the process of altering the mechanics of her serve, produced nine double faults as she lost 7-6 6-3 to Pennetta in Indian Wells.

"I don't think I was playing bad," Li told reporters. "I think it was a pretty high level match. Some points I was feeling I still had a chance but on the more important points I got double faults."

On her new serve, she added: "Of course if I want to change something, you cannot change for one or two days. You need time to organise everything.

"I was feeling better and better. I should be OK in the next tournament or the tournament after that."

Pennetta will face Agnieszka Radwanska in the final, after the Pole recorded a straight-sets victory over Simona Halep in the other last-four match.