Tianjin - Top-seeded Jelena Jankovic was upset by Zheng Saisai of China 6-3, 6-3 in the second round of the Tianjin Open on Thursday.
The 112th-ranked Zheng converted five of nine break points against Jankovic to notch her first career win over a top-20 player.
Hometown favorite Peng Shuai, seeded second, also advanced to the quarter-finals with a 6-1, 6-2 win over qualifier Elizaveta Kulichkova of Russia.
Peng, the top-ranked Chinese player now that Li Na has retired, reached the U.S. Open semi-finals last month but is still looking for her first WTA Tour title.
Also, Hsieh Su-Wei of Taiwan topped fifth-seeded Zhang Shuai of China 3-6, 6-3, 7-6 (5).
Tianjin Open results on Thursday:
Zheng Saisai (CHN) bt Jelena Jankovic (SRB x1) 6-3, 6-3
Hsieh Su-Wei (TPE) bt Zhang Shuai (CHN x5) 3-6, 6-3, 7-6 (7/5)
Peng Shuai (CHN x2) bt Elizaveta Kulichkova (RUS) 6-1, 6-2