?Li Na of China serves the ball during the women's singles quarterfinal match against Anastasija Sevastonva of Latvia at the China Open tennis tournament in Beijing, capital of China, Oct. 8, 2010. [Xinhua/Chen Jianli]

Ninth seed Li Na reached her first semifinals at China Open on Friday as she managed to defeat Anastasija Sevastova of Latvia 7-6(6), 6-3 in the quarters.

World No. 55 Sevastova, a qualifier and the lowest-ranked player remaining, had a sound performance in her debut at Beijing, ousting world number seven Samantha Stosur and Dominika Cibulkova en route to the quarters. She eased through third round as her opponent Nadia Petrova, who beat Li six times in a row before, quitted the match due to injury.

"I know nothing about her(Sevastova), therefore I was very passive on the court," said Li, ranked world number 15 and still in the race to qualify for one of the two remaining spots at Doha's WTA championships.

The 20-year-old Latvian had a better start by breaking Li to go ahead 2-0. Home favorite Li, cheered by the spectators in Lotus Court, broke back to tie for 2-all. The two players entered into the tiebreaker after trading three service breaks. Trailing by 3-5 in the tiebreaker, Li stood with the pressure, using heavy services and crosscourt hits to take it 8-6.

The first set seemed to energize Li and unsettle Sevastova. The experienced Li was calm and composed, letting her opponent make mistake after mistake, eight unforced errors and three double-faults in the second set. Li broke twice to concluded the match and set a clash with the second seed Vera Zvonareva, who beat the fifth seed Francesca Schiavone with a quick victory of 6-0, 6-2.

"I won the match thanks to my experience and my performance in the key points," Li said.