Li Na moves up in rankings, Azarenka, Sharapova, S. Williams lead Li Na, shown at the 2012 U.S. Open, improved to No. 6 in this week's WTA rankings, the last update before the Australian Open. DAYTONA BEACH, Fla., Jan. 7 (UPI) -- Top-10 players Serena Williams, Agnieszka Radwanska and Li Na all picked up tournament titles last week but only Li improved her WTA ranking. Williams won the Brisbane International, Radwanska was the champion at the ASB Classic in New Zealand and Li took the title in Shenzhen, China, all on Saturday. Each player gained additional ranking points but only Li moved in the rankings. She's now sixth, edging by Sara Errani. That was the only change in the WTA Top 10 ahead of this week's seedings and draw for the Australian Open, which begins Jan. 14. Victoria Azarenka, who withdrew last week before a semifinal match against Williams, continues to lead the rankings, with Maria Sharapova, who pulled out of the tournament in Brisbane due to injury, second. Azarenka has 10,595 ranking points and Sharapova 10,045. Williams remains third but has pulled up to 9,750 points. Radwanska, ranked fourth, has 7,505. 5-ranked Angelique Kerber has 5,550 points, not far ahead of Li, who had 5,255 points in sixth. Errani comes in a close seventh with 5,100 and No. 8-ranked Petra Kvitova is right behind with 5,085 points. Samantha Stosur sits in ninth with 4,135 points and Caroline Wozniacki, with 3,765 points, is 10th. All but the top three in the rankings were entered into this week's Apia International n Sydney. Petrova, dropped her first-round match Monday.