Hantuchova remains on course

The Slovakian, who won the Pattaya title in both 2011 and 2012, will now challenge China’s Ying-Ying Duan for a place in the last four following her 7-6 (7/5) 6-2 defeat of Zheng.

Duan reached the next round after her compatriot Lin Zhu retired while trailing 6-1 0-0.

Fourth seed Evgeniya Rodina progressed with a 6-2 6-4 trumping of Japan’s Kurumi Nara and will next tackle Ajla Tomljanovic, who ousted Jarmila Gajdosova 7-6 (7/3) 6-3.

The other quarter-finals pit Misaki Doi against seventh seed Monica Puig of Puerto Rico and former world number two Vera Zvonareva against Marina Erakovic.