Guus Hiddink feels that Chelsea goalkeeper Petr Cech is suffering from a lack of confidence.
Cech has conceded seven goals in his last two appearances following the 4-3 Premier League win over Bolton and 4-4 UEFA Champions League draw with Liverpool.
The Czech international came in for specific criticism after he was caught out by Fabio Aurelio's free-kick for the Reds' opener on Tuesday night.
Of Cech's state of mind, Blues manager Hiddink said: "He is a very intelligent and self-critical goalkeeper.
"He was not happy with his performance against Bolton although there was always a sequence of errors before he came into action. But he is very critical of his own performance even when he has had an almost perfect game.
"There were some things tonight [Tuesday] where you could see he was not full of confidence. I think a goalkeeper once in a while has a right not to have a big performance.
"But he will stay a very good goalkeeper, every person sometimes has this small period of not being on top form. If a player is playing a lesser game now and then, it is not always the reason to make a substitution."
Cech concedes his recent form has dipped but remains hopeful he will not be dropped for the Blues' FA Cup semi-final clash against Arsenal on Saturday.
"I would be disappointed to be left out against Arsenal. Who wouldn't be? This is a question for the manager, but one bad goal can't change what you have been doing all season," said Cech.
"You have to show your confidence in training and in games.
"If you go to speak to the manager, you can say whatever you want, but he needs to see your answers on the pitch, not in his office. In any case, I am sure we won't defend as badly again on Saturday.
"It is the first time in my Chelsea career that I have conceded so many goals in two consecutive games, and the first time I have made mistakes in both of them."