The construction mogul underlined that the job of the head coach at the Spanish capital club is very challenging and requires adaptation on behalf of the trainer, which did not come easy for 'The Special One'.
"'Mou' took a while to understand what Madrid is. He's coached in Portugal, Italy and England but this is something else. This is Madrid. We understand our own culture. But those who come in from outside don't understand it," Perez told AS.
"When 'Mou' arrived, he clashed with the club, the people, the fact that the fans would whistle at some players or even the coach. That's even happened with some recently arrived players and they've got it wrong a number of times.
"But they've learnt. 'Mou' knows he's worked at a number of clubs at the highest level. But as I tell him, Madrid comes first, next and after that. That's the distance between us and the rest."
Perez also conceded that the club passed on the chance to sign Manchester City star David Silva before they opted to buy Mesut Ozil from Werder Bremen.
"I believe that we have best squad in Madrid's history. We could have signed Silva, but I preferred Ozil. Silva is a great player, and on top of that he is Spanish. We like great players."
The club president also had a word on Brazilian star Kaka, who has been linked with an exit from the Madrid club.
"Great players and Ballon d'Or winners like Cristiano and Kaka make it possible to make more revenue. In some cases, they have bad luck and suffer with injuries. We hope to have Kaka great again."