GUANGZHOU, China - No.4 seed Petra Martic, the only seed in action Monday at the WANLIMA Guangzhou International Women's Open, is into the second round after a 64 64 defeat of Chang Kai-Chen.

Martic is having her best year on the WTA, having reached her first two semifinals at Bogotá and Copenhagen. She also rose to a career-high No.54 earlier this month and is Croatia's top-ranked player.

"It was a very tough match today," said Martic, currently ranked 55th. "She played very well, very aggressive. I tried to mix up the rhythm, go for my shots, dictate play, and it worked out well."

Another of Monday's winners was Urszula Radwanska. Coming off her career-best showing, a run to the final four last week in Tashkent, the Pole rallied from a 5-3 deficit in the first set tie-break en route to beating Anastasia Rodionova, 76(5) 64.

Noppawan Lertcheewakarn was down a set point at 5-4 on Zheng Saisai's serve, but not only won that game but the eight that followed in recording a 75 60 triumph. The Thai saved 11 out of 13 break point opportunities while converting on six out of 10 on Zheng's serve.

Advancing to the main draw with wins in qualifying were Zhao Yi-Jing, Zarina Diyas, Hsieh Su-Wei and Xu Yi-Fan.

No.1 seed Maria Kirilenko, No.2 seed and defending champion Jarmila Gajdosova and No.3 seed Ksenia Pervak - fresh off her first career title in Tashkent - are among those who play their openers on Tuesday. Kirilenko could have her hands full, as he has lost her last two encounters with her opponent - former Top 20 player Alona Bondarenko.