Li Na of China returns a shot to Angelique Kerber of Germany during their match at the round-robin stage of the WTA Championships tennis tournament in Istanbul, Turkey, Oct 25, 2012. [Photo/CFP]

ISTANBUL - Chinese tennis player Li Na kept her hope of reaching the semifinals of the WTA Championships alive on Thursday with a 6-4, 6-3 win over German player Angelique Kerber.

Li was going through the gears, taking the ball early and swatting forehands and backhands for winners seemingly at will. She quickly moved a couple of breaks ahead and, despite a late wobble, she gathered herself once more to serve the match out to love.

"I had my first match yesterday but felt much, much better today. I was more focused and concentrated on the court," Li said.

"Angelique is very good in defense. My coach, Carlos, was telling me before the match to use more top-spin and open the court. I knew I had to change the space to win today."

In her final red group match, Li takes on top seed Victoria Azarenka on Friday. The winner will join Serena Williams in the semifinals after she guaranteed top spot with a 6-4, 6-4 win over the Belarussian.

Having lost her opening two matches in the tournament, Kerber knew that a comfortable win was required for her to have any chance of reaching the weekend.