A knife-wielding intruder attacked two-time Wimbledon tennis champion Petra Kvitova in her apartment in the Czech Republic on Tuesday, with one media outlet reporting her playing arm had been injured.

The world number 11 said she was still waiting for doctors to tell her the extent of her injuries. "The worst is already behind me," she said in a statement issued on the Czech Republic Fed Cup team's Facebook page.

Kvitova was assaulted in her home in the city of Prostejov, about 260 km southeast of Prague, media reported. A spokeswoman for the city hospital said she had been treated for a knife injury, without going into further detail.

"What has happened to me was not pleasant at all, but it is already behind me," Kvitova said in the statement on Facebook.

"The main thing for me now is that the doctors will determine how my hand is doing. I trust them and I believe that it will end well," she added.

Her spokesman Karel Tejkal told CTK news agency the attack had been "a random criminal act". "She was assaulted in her apartment and is in the care of doctors, but her injuries are not life-threatening," he added.

Czech Radio reported the injury was to Kvitova's left hand, which she plays with.