Their defending for Ezequiel Lavezzi's two goals in Napoli's 3-1 win in Italy on Tuesday was far from impressive.
And Cech said: "We know he (Villas-Boas) keeps working hard for us.
"He prepares every game with 100% commitment and we appreciate it as players.
"But if you have players on the pitch making mistakes he can't help it."
The Czech Republic international continued on Sky Sports: "I think it was an amazing game for the supporters to watch, there were a lot of counter-attacks, shots and chances.
"But if you come to a place where they are strong at scoring and leave them so many moments you can get punished.
"We went 1-0 up and had a spell where we controlled the game but they got a goal just before half-time that made a difference because they could sit back and wait for the counter-attack.
"We tried to score and it became dangerous for us as they looked for a third goal."









