The Russian, who claimed her first title since returning from a shoulder injury in Tokyo on Saturday, had to come from 5-2 down in the third set to win a three-hour opening match on Tuesday.

There was to be no way back against Peng, however, and the world number 53 converted her third match point to upset a high profile player for the second evening in a row after her second-round win over defending champion Jelena Jankovic.

Fourth seed Elena Dementieva restored order in the second Russia versus China clash of the evening, rattling through her third round match against Li Na 6-2, 6-0 in just under an hour to move into the quarterfinals.  Svetlana Kuznetsova, the 2006 China Open champion, overcame a misfiring serve to claim her place in the last eight with a 6-3, 4-6, 6-0 victory over Ukraine's Alona Bondarenko.

Anastasia Pavlyuchenkova beat Canadian Aleksandra Wozniak 6-4, 6-4.
Men's fourth seed Nikolay Davydenko earlier boosted his chances of reaching the ATP Tour's season finale for a fifth time with a 6-1, 6-0 thrashing of Philipp Kohlschreiber.
Second seed Novak Djokovic later claimed a place in the men's last-eight with 6-3, 6-0 demolition of fellow Serb Viktor Troicki.

Spain's Fernando Verdasco defeated Juan Carlos Ferrero 7-5, 6-4.

Tsonga advances

Second seed Jo-Wilfried Tsonga blasted past Germany's Mischa Zverev 6-4, 6-3 to reach the last 16 of the Japan Open on Wednesday.

The Frenchman will play countryman Richard Gasquet in the next round after the former top-10 player thrashed German Philipp Petzschner 6-3, 6-2.