Seventh-seeded Daniela Hantuchova was upset by Agnieszka Radwanska 6-3, 6-3.

Henin had four double faults in the opening set. The top-ranked Belgian made the decisive break at 3-3 when Zvonareva hit the ball long, and then broke again at 5-3.

In the second set, Zvonareva only held her opening serve. At 2-1, Henin built up three break points but needed only one, taking the game with a cross court forehand winner. She broke twice more to close out the match.

"It was tough for me at the beginning of the match to find a good rhythm," Henin said. "I needed to get used to the conditions. But at 5-3 and then the second set I started to play better."

Hantuchova struggled with a cold, and the loss hurt her chances of qualifying for the season-ending WTA Championships in Madrid, Spain.

"I had a really hard time today trying to catch my breath in between points," Hantuchova said. "I have been fighting a cold for the past few days and I really just had nothing left and became very tired out there."

It was the first meeting for the pair.

"This is a huge success for me to be in the quarterfinals of a tournament like this," said Radwanska, ranked 31st.

Hantuchova was the fifth of eight seeded players to exit early.

Third-seeded Jelena Jankovic and fifth-seeded Ana Ivanovic, both of Serbia, were defeated along with Amelie Mauresmo, seeded eighth. Sixth-seeded Serena Williams withdrew with a sore thigh on Tuesday.