China's Li Na fought back from a set and a break down to delay Petra Kvitova's bid for the world number one ranking in a tenacious semi-final victory at the Sydney International on Thursday. French Open champion Li recovered to down Wimbledon winner Kvitova 1-6, 7-5, 6-2 in two hours of high-class tennis to reach her second consecutive Sydney final. In doing so world number five Li ended the Czech left-hander's hopes of toppling Caroline Wozniacki from the top of the women's rankings ahead of next week's Australian Open in Melbourne. Li is the first women's player to play in back-to-back Sydney finals since Russia's two-time champion Elena Dementieva in 2009-10. Li will face either Belarussian third seed Victoria Azarenka or Polish seventh seed Agnieszka Radwanska in Friday's final. Radwanska upset Wozniacki in three sets in Wednesday's quarter-final to advance to her semi-final with Azarenka later Thursday. Li looked headed for defeat when Kvitova stormed through the opening set for the loss of one game and broke early in the second set to lead 3-1, but the Chinese star turned around the match with fearless serving and shot-making. Several times Li saved break points with a brave deep second serve to keep in the match. But as Li continued to frustrate Kvitova's attempts to finish off the match she gradually clawed back to finish the stronger. Li now leads Kvitova 2-1 in their matches. It was Li's fourth win this week, continuing her upsurge in form after a dismal follow-up to her landmark French Open success over Italy's Francesca Schiavone at Roland Garros, which saw her become the first Asian to win a grand slam title. Li, 29, who only won seven matches in the second half of 2011 after her French Open breakthrough, said this week she was back in the form she had enjoyed prior to Wimbledon, where she bowed out to Germany's Sabine Lisicki in the second round.