Updated

Tianjin, China (SportsNetwork.com) - Top-seeded former world No. 1 Jelena Jankovic came up a second-round loser Thursday at the inaugural Tianjin Open.

China's own Zheng Saisai upended the Serbian veteran Jankovic 6-3, 6-3 on the hardcourts at Tianjin International Tennis Center.

Meanwhile, second-seeded Chinese Peng Shuai whipped Russian qualifier Elizaveta Kulichkova 6-1, 6-2 and Taiwan's Su-Wei Hsieh upended fifth-seeded Chinese Zhang Shuai 3-6, 6-3, 7-6 (7-5) on Day 4.

Friday's quarterfinals will pit Peng against eighth-seeded Croat Ajla Tomljanovic; third-seeded Swiss teenager Belinda Bencic versus Hsieh; fourth-seeded Varvara Lepchenko against sixth-seeded fellow American Alison Riske; and Zheng versus Romanian Sorana Cirstea.

This week's winner will claim $43,000.