FILE - In this Oct. 4, 2016, file photo, Petra Kvitova, of the Czech Republic, watches her shot during her women's singles match against Wang Yafan of China at the China Open tennis tournament in Beijing. Two-time Wimbledon champion Petra Kvitova is back at practice, less than six months after being attacked by a knife-wielding intruder. Kvitova posted a photo on Instagram on Tuesday, May 2, 2017, showing herself swinging a tennis racket. (AP Photo/Andy Wong, File)