Czech sixth seed Petra Kvitova has edged into the third round of the women's Olympic singles with a narrow three-set victory over China's Shuai Peng.
The former Wimbledon champion lost her opening service game but soon rallied to take the first set 7-5.
However, world number 29 Peng broke twice in the second as she eased to a 6-2 triumph.
The third began with a lengthy game on Peng's serve which Kvitova finally broke to give herself the initiative. From there it was straightforward for the Czech as she closed out the match 6-1.
Kvitova will meet either Russian third seed Maria Sharapova or Britain's Laura Robson for a place in the quarter-finals.
