Azarenka, a former champion here back in 2009 defeated 2010 champion Clijsters in straight sets, winning 6-3 6-3 in one hour and 21 minutes.

With 44 unforced errors and just 54 percent first service rate, Clijsters struggled with her game and 8th seed Azarenka took full advantage of the lacklustre performance from the Belgian.

"I just didn't feel good out there. Just mentally and physically, I didn't feel right," said Clijsters after the match.

"It has been a tough few last days but not in a way that I should not be ready for that. I train hard enough to physically be capable of doing that.

It's obviously tough against someone like her. Against some lower ranked players maybe it's possible to get through matches, but against somebody like her it isn't,"

Azarenka will now go on to face world number three Vera Zvonareva of Russia in the semi-finals after she beat Agnieszka Radwanska of Poland 7-5 6-3.