Police said the man posed as a boiler repair engineer to gain entry into her apartment block but would not be drawn on whether he had deliberately targeted the tennis player.

Kvitova, the Czech Republic’s most famous female athlete, said in a statement posted on her Facebook and Twitter pages: “Thank you for all your heartwarming messages.

“As you may have already heard, today I was attacked in my apartment by an individual with a knife. In my attempt to defend myself, I was badly injured on my left hand.

“I am shaken, but fortunate to be alive. The injury is severe and I will need to see specialists, but if you know anything about me I am strong and I will fight this. Thank you all again for your love and support and now I would appreciate some privacy while I focus on my recovery.”

After surgery was competed, her PR manager said: "Doctors are optimistic she will be able to play tennis again.

"Petra had surgery for three hours, 45 minutes. Considering the damage to her left hand, it was a success.

"She had tendon damage to all five digits on her left hand, and nerve damage to two of them.