Russia's Maria Sharapova became the latest upset victim at the China Open on Wednesday, while compatriots Nikolay Davydenko and Svetlana Kuznetsova sailed into the quarterfinals in Beijing.

Sharapova, a three-time Grand Slam winner, made 21 unforced errors and surrendered her serve four times in the 6-2, 6-4 loss to China's Peng Shuai on centre court at the Olympic tennis venue.

The 22-year-old Russian, ranked 15th in the world, looked sluggish, with her ferocious ground strokes too often landing in the net or beyond the baseline, while the 53rd-ranked Peng remained solid, making just three unforced errors.

Sharapova saved two match points in the final game, but handed Peng the victory on her third attempt by netting a forehand.

Sharapova is not the only star to make an early exit from the $6.6-million mixed ATP/WTA event.

Dinara Safina and Venus Williams — along with defending champions Jelena Jankovic and Andy Roddick — have also been ousted from the tournament.

Fourth seed Davydenko, who won his third ATP title of the year in Malaysia last weekend, trounced Germany's Philipp Kohlschreiber, allowing the world number 22 only one game in a 6-1, 6-0 romp.

The 28-year-old Russian, the world number eight, is fighting to secure a place in the season-ending ATP World Tour Finals in London in November, which will feature the top eight men's singles players.

Roddick, Fernando Verdasco, Fernando Gonzalez and Robin Soderling are also vying for the final three spots in the London draw. Roger Federer, Rafael Nadal, Andy Murray, Juan Martin del Potro and Novak Djokovic have qualified.

Besides Roddick, the other London hopefuls are all still in contention in Beijing.

In the quarterfinals, Davydenko will face Croatian eighth seed Marin Cilic, who rallied to defeat France's Julien Benneteau in three sets, 6-2, 2-6, 6-0.

On the women's side of the draw, two other Russians had better luck than Sharapova.

Kuznetsova, the sixth seed, lost her focus mid-match but stormed back in the third set to beat Ukraine's Alona Bondarenko, 6-3, 4-6, 6-0.

The two-time Grand Slam winner took control of the first set with a service break to go up 4-2 and closed it out easily, using her big forehand to get herself out of trouble on key points.

But the 24-year-old faltered in the second, having trouble with her serve and losing her range from the baseline before surrendering the set to the 25-year-old Ukrainian.

Kuznetsova then showed some grit, breaking Bondarenko at the start of the deciding set and cruising to victory without dropping another game.

Talented teen Anastasia Pavlyuchenkova, who upset world number three Williams on Monday, continued her winning ways, defeating Canada's Aleksandra Wozniak in straight sets, 6-4, 6-4.

Kuznetsova and the 18-year-old Pavlyuchenkova will face off in an all-Russian quarterfinal.

Another Russian, world number four Elena Dementieva, was due on centre court later Wednesday, along with Djokovic.