West Ham manager Slaven Bilic believes Manchester City are struggling for confidence because of Pep Guardiola's tactics.
City are fourth in the Premier League but have been in scratchy form, including suffering a 1-0 loss to Liverpool on New Year's Eve.
Bilic, whose team face City in the FA Cup on Friday, feels recent losses - including a three-match winless run to start December - have had an impact.
"After you have three or four wins on the trot then the opponent may be pressing you but you are not scared," he told UK newspapers.
"OK, you can occasionally lose the ball but you don't care. At the end of the day, it's the plan.
"But after you make some mistakes and it ends in defeat then you think twice about it. You try it again but you are not that confident any more. It's like a chain."
However, Bilic said players needed to take more responsibility for their performances.
The Croatian, whose side are 13th in the Premier League, said philosophy was one thing - but players needed to be accountable.
"The manager has his philosophy and everything and the manager guides you as a player but at the end of the day it's your decision," Bilic said.
"If you are in the box, if you don't know where you are because you were ball watching and you are in front of your goal, no manager is expecting you to get the ball on your chest. It's always the player's decision.
"If you are talking about Guardiola I have seen so many times Gerard Pique putting the ball in the stands [at Barcelona] when necessary. It's the player's decision always."