BEIJING — Li Na reached the quarterfinals of the China Open by edging Sabine Lisicki 7-5, 6-4 on Wednesday.
In men's play, Rafael Nadal, aiming to end Noavk Djokovic's run of 100 weeks at the top of ATP ranking, beat Germany's Philipp Kohlschreiber 6-4, 7-6 (3) to move into the third round. Nadal could replace Djokovic as No. 1 if he qualified for the final.
American John Isner defeated Roberto Bautista Agut of Spain 6-2, 6-7 (3), 6-4, and Fabio Fognini of Italy routed Lleyton Hewitt 6-0, 6-2.
Li broke Lisicki twice in each set, overcoming seven double-faults and holding off six of eight break chances. Fifth-ranked Li, who reached the semifinals in 2010 and 2012 in Beijing, will face No. 7 Petra Kvitova.
Kvitova beat Sara Errani of Italy 6-4, 6-7 (3), 6-3 in a match that featured 19 breaks of serve. Li holds a 3-2 record against Kvitova.
At Tokyo, top-seeded Juan Martin del Potro advanced to the Japan Open quarterfinals with a comfortable 6-2, 6-2 win over fellow Argentine Carlos Berlocq.
Del Potro broke Berlocq's serve twice in the second set and closed out the match in 1 hour, 6 minutes.
In the day's only upset, Ivan Dodig of Croatia ousted second-seeded Jo-Wilfried Tsonga of France 6-4, 7-6 (5).
In other matches, third-seeded Milos Raonic of Canada advanced to the second round with a 6-4, 7-6 (0) win over Go Soeda of Japan in the opening match on Center Court.