World number four Agnieszka Radwanska powered her way through to the last 16 of the China Open with a convincing victory over American teenager Madison Keys on Wednesday.

The Polish third seed took one hour and 15 minutes to claim a 6-3, 6-2 victory over the 18-year-old, who is being tipped as one of the rising stars of women's tennis.

Radwanska, a previous winner in Beijing in 2011, had defeated Keys at Wimbledon in the summer, and praised her opponent after their meeting at China's National Tennis Centre.

"I think she's one of the youngest talented players coming out," she told reporters after the second-round match.

"I think in a couple of years we are going to see her more often, definitely."

Elsewhere, Andrea Petkovic continued her stunning form at the tournament by dumping out former Roland Garros winner Svetlana Kuznetsova 4-6, 6-4, 6-1 in her second-round match.

The German, who is ranked 43 in the world, took just over two hours to claim victory over the 25th-ranked Russian, a previous winner in Beijing in 2006 and 2009.

Petkovic's victory over the 2009 French Open singles champion follows her stunning first-round defeat of second seed and current Beijing champion Victoria Azarenka.

The 26-year-old said claiming the scalps of both the Belarusian -- who won the Australian Open for the second time earlier this year -- and Kuznetsova had given her confidence a massive boost.

"This is the first tournament that I've been able to really keep up my intensity and keep up my focus. I think I played two good matches," she told reporters.

"For me, just 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."

Elsewhere, eighth seed Jelena Jankovic of Serbia booked her place in the last 16 with a 6-3, 5-7, 6-3 victory over Kazakhstan's Galina Voskoboeva, and Slovenia's Polona Hercog defeated 14th seed Ana Ivanovic of Serbia 6-4, 6-4.

In the men's tournament, eighth-seed American John Isner beat Spaniard Roberto Bautista Agut 6-2, 6-7, 6-4, and Australia's former world number one Lleyton Hewitt suffered a crushing 6-0, 6-2 defeat at the hands of Fabio Fognini.

The Italian will face second seed Rafael Nadal in the quarter-finals if the Spaniard overcomes Germany's Philipp Kohlschreiber in his Wednesday evening match.

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