Agnieszka Radwanska of Poland serves to Stefanie Voegele of Switzerland in their women's singles first round match at the China Open tennis tournament in Beijing, Sept 29, 2013. [Photo/icpress.cn]

Radwanska, however, battled for more than two hours to make it past Stefanie Voegele 4-6, 6-4, 6-4.

After dropping the first set, the star from Poland faced some tricky moments early on in the next two sets - she faced break points in her first two service games of the second set, and actually lost serve in the first game of the third. But she stayed cool, calm and collected through it all and got her nose in front again every time, eventually making it past the Swiss in two hours and 14 minutes.

"The first match is always tricky, especially because each week we have different conditions, different courts and different balls," Radwanska said afterwards. "I needed this match just to feel the rhythm."

Next up for Radwanska is American Madison Keys, who put on a serving display -- eight aces, zero double faults - and took out Dominika Cibulkova of Slovakia at 6-4, 6-3.

Elsewhere, Lucie Safarova of the Czech Republic pulled off a 7-5, 6-3 upset over No 15 seed and former US Open winner Samantha Stosur of Australia, and Maria Kirilenko of Russia battled through Chinese Zheng Jie to also make it into second round.