Cardiff boss Dave Jones pointed his finger at his leaky defence after a disappointing 1-0 defeat at Middlesbrough.
Boro, whose backline had to cope with the absence of suspended centre-back David Wheater, got their only goal through a first-half Julio Arca penalty, converted after after Gabor Gyepes brought down Marvin Emnes in the box.
Jones said: "I don't know how often we are going to leave the door open at the back. A bit of fear has crept in there somehow. At the moment that unit isn't working.
"We are the second biggest scorers so there is nothing wrong going forward but if you don't score you have to keep a clean sheet and that isn't happening and too often we end up chasing the game.
"I wouldn't mind if we were beaten by good movement but it was a punt down the middle and a sloppily conceded penalty and that shouldn't happen.
"We have to make sure we don't get carried away and let a blame culture creep in but right now they need a bit of criticism. It is harsh but they have to accept it."