Oct 2 (Reuters) - Home favourite Li Na overcame Germany's Sabine Lisicki 7-5 6-4 at the China Open on Wednesday to set up a quarter-final showdown with former Wimbledon champion Petra Kvitova.
The Czech, who won the Japan Open last weekend, overcame Italian fifth seed Sara Errani 6-4 6-7(3) 6-3 in their third round clash at the prestigious $5 million Beijing tournament.
World number four Agnieszka Radwanska was one of a number of high profile women to win through in second round action on the hard courts at the National Tennis Centre as the Pole dispatched promising American Madison Keys 6-3 6-2.
Radwanksa will next face Slovenian wildcard Polona Hercog, who stunned former world number one Ana Ivanovic 6-4 6-4 in the day's only upset.
"It was a big challenge for me to go out there on a big court and play against Ana Ivanovic, and I'm just really happy the way it turned out," Hercog told the WTA Tour. "It's probably one of the biggest victories for me."
Germany's Andrea Petkovic provided the upset of the first round when she ousted Australian Open winner Victoria Azarenka and the Bosnia-born world number 43 followed that up with a second round win over another grand slam champion on Wednesday.
Petkovic again needed to go the distance as she beat former French and U.S. Open champion Svetlana Kuznetsova 4-6 6-4 6-1.
"This is the first tournament that I've been able to really keep up my intensity and keep up my focus. I think I've played two good matches," Petkovic said after setting up a clash with Czech Lucie Safarova in the third round.
"Personally it's really important to see that I can still beat the players on the top level, two past grand slam champions. It's just a big boost for my confidence, no matter what happens now in the future."
The victories though were only warm-up acts for the home fans keen to see their compatriot Li in action.
Li, the first Asian to win a grand slam singles title when she triumphed at the 2011 French Open, had the crowd happy as she scored a break in her 13th seeded opponent's first service game.
The world number five ran in to trouble though as she attempted to serve out the set as Lizicki broke back to level at 5-5 only for Li to break again and win it 7-5.
Another break came midway through the second set as Li wrapped it up 6-4 despite a match total of seven double faults.
That serving issue will need to be resolved if she is to find a way past in-form Kvitova.
World number one Serena Williams is back in action on Thursday when she takes on Maria Kirilenko in the third round.
(Writing by Patrick Johnston in Singapore, editing by Pritha Sarkar)