Updated

Shenzhen, China (SportsNetwork.com) - Top seed and defending champion Li Na of China and surprising American Vania King were among Thursday's quarterfinal winners at the $500,000 Shenzhen Open tennis event, a hardcourt Australian Open tune-up.

The 31-year-old Li snuck past game Romanian Monica Niculescu 7-5, 4-6, 6-4, while the 24-year-old King straight-setted Czech Barbora Zahlavova Strycova 6-2, 6-4 at Shenzhen Longgang Tennis Center.

The 2013 Aussie Open runner-up Li will encounter eighth-seeded German Annika Beck in Friday's semifinals, while King will take on fifth-seeded Chinese Peng Shuai. Wins by Li and Peng would produce a popular all-Chinese final on Saturday.

Two other quarterfinals saw Peng paste Slovak Jana Cepelova 6-3, 6-2 and Beck overcome Austrian Patricia Mayr-Achleitner 3-6, 6-3, 6-1.

The world No. 3 former French Open champion Li won last year's inaugural Shenzhen title by beating Czech Klara Zakopalova in the finale.