Clijsters through to semis

The first set was dominated by the Belgian before Zvonareva - who won in Cinncinatti last week - adapted her game and appeared to be getting to grips with her opponent's power and accuracy.

But living up to her top-seed billing, Clijsters managed to re-focus and ran away with the third set, to set up a last-four meeting with Czech teenager Nicole Vaidisova.

She said: "I was making too many unforced errors in that second set and I refocused. I served more consistently and it gave me better opportunities to play aggressive.

"She plays aggressively, so if you don't, she can move you around. So when I got a chance to dominate from the first ball, I tried to go for it."

Vaidisova moved comfortably through her quarter-final match 6-4 6-2, battering Australian Sam Stosur with her big serves and heavy groundstrokes.

The 17-year-old said: "I didn't start out the greatest, but I stayed positive and was able to come back and play well.

"I didn't have that much trouble with her serve and tried to change the pace sometimes. I'm excited to be in the semi-finals."

In the other quarter-finals, second seed Patty Schnyder booked her semi-final place by beating American Jill Craybas 6-4 7-5 and will now meet Tatiana Golovin. The French teenager - who is coming back from an ankle injury that sidelined her for two months earlier in the year – defeated fourth seed Anna-Lena Groenefeld 6-4 7-6