Updated

World No. 1 Victoria Azarenka and second seed Maria Sharapova were easy quarterfinal winners Friday at the $4.8 million China Open tennis event.

The Australian Open champion and U.S. Open runner-up Azarenka, of Belarus, blew past Swiss Romina Oprandi 6-2, 6-0 in 55 minutes, while the French Open champion and former No. 1 Sharapova, of Russia, was pasting fifth seed Angelique Kerber 6-0, 3-0 when the German retired due to a right foot injury after 53 minutes of lopsided tennis.

"I thought we played a high level of tennis the first set and a half, there were many games that went to deuce," Sharapova said. "I was surprised she called the trainer and even more so when she retired quickly after that."

Azarenka's semifinal opponent will be ninth-seeded French slugger Marion Bartoli, while Sharapova will take on seventh-seeded heavy Chinese crowd favorite Li Na.

Li ousted third-seeded and defending Beijing champion Agnieszka Radwanska 6-4, 6-2, while Bartoli held off Spaniard Carla Suarez Navarro 6-0, 2-6, 6-4 on the hardcourts at the National Tennis Centre.

The 2012 Wimbledon runner-up Radwanska beat German Andrea Petkovic in last year's Beijing finale and was a China Open runner-up in 2009. Radwanska was also a runner-up in Tokyo last week.

On Saturday, Azarenka will face Bartoli for a 12th time on the WTA tour, seeking a ninth win in their lifetime series, while Sharapova is 7-4 all-time versus Li heading into their semi affair. Azarenka and Bartoli have split a pair of meetings this year, while Sharapova is 2-0 against Li in 2012.

The 2012 Beijing titlist will collect $848,000.