Beijing: World number four Victoria Azarenka of Belarus Thursday pulled out of the China Open tennis due to a foot injury after reaching the pre-quarterfinals.
Azarenka said: "It is disappointing to have to withdraw from China Open. I am sorry to the fans. I was hoping that my foot would be okay, but it has been bothering me since Tokyo. I am not sure about the recovery time yet, but I will continue to consult with my doctor. I expect to be back for Luxembourg."
Her opponent Anastasia Pavlyuchenkova of Russia will get a walkover to the quarterfinals.
The China Open, which is running in its eighth year, has lost Novak Djokovic, Maria Sharapova and the Williams sisters to injury or illness prior to the event.
Second seed Gael Monfils of France and Russian veteran Nikolay Davydenko also announced decision to withdraw after the elite tournament kicked off Saturday.
It was then followed by early upsets from reigning Grand Slam winners Li Na of China (French Open), Petra Kvitova of the Czech Republic (Wimbledon) and Australia`s Samantha Stosur (US Open).