BEIJING -- Li Na reached the quarterfinals of the China Open by edging Sabine Lisicki 7-5, 6-4 on Wednesday.
In men's play, 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.
Former champions Agnieszka Radwanska (2011) and Jelena Jankovic (2008) won their second-round matches. Fourth-ranked Radwanska defeated American Madison Keys 6-3, 6-2, and 11th-ranked Jankovic stopped Galina Voskoboeva of Kazakhstan 6-3, 5-7, 6-3.
Two-time former winner Svetlana Kuznetsova lost to Andrea Petkovic 4-6, 6-4, 6-1.
Polish qualifier Polona Hercog ousted Ana Ivanovic 6-4, 6-4 and will play Radwanska for a spot in the last eight.