BOGOTÁ, Colombia - Only two seeds remain at an upset-ridden XIX Copa BBVA Colsanitas following the takedown of No.1 seed Julia Goerges and No.2 seed Polona Hercog.

Han Xinyun found herself in a nerve-wracking situation as she took the court Thursday, serving for the match up 5-4 in the third set against Goerges following Wednesday's rainout of their second round match. Sure enough, she got broken but settled her nerves and later held serve at 5-6 to force the tie-breaker, which she won by taking the last three points when it was knotted at 4-4 for a final score of 57 63 76(4).

"I played Julia three years ago and she is a great player, so I just tried to keep the ball deep," said Han, who also won her one previous encounter with the German. "I played great in the second, and in the third set we were very close before the rain. We were both really nervous today, but I was patient, and I took a chance to win the tie-break."

The 34th-ranked Goerges is the highest-ranked player Han has ever beaten, and the Chinese will be trying to go deeper in a draw than she ever has when she takes on fifth-seeded Carla Suárez Navarro in Friday's quarterfinals. Han's only previous quarterfinal appearance occurred in Guangzhou last September, which in fact was the last time she won a WTA match before this week.

Thursday's other surprise saw Petra Martic easily dispose of Hercog, 62 63, to reach her first quarterfinal since Portoroz in July 2009.

"I played well and I'm happy with my performance," said Martic, who like Han will be going for her first career semifinal when she plays Laura Pous-Tio on Friday. "This was my first time playing in high altitude and I think I adjusted well. It was a straight set win, so I'm very happy."

Coincidentally enough, just like Han on Thursday, Beatriz García Vidagany will serve for the match up 5-4 in the third when her rain-suspended match against fellow qualifier Corinna Dentoni resumes Friday. The winner of that will play No.7 seed Lourdes Domínguez Lino later on Friday.