The shot-stopper reportedly endures a difficult relationship with the Portuguese coach, but Casillas has nothing but praise for 'the Special One'.
"Until you meet him you don't realise that he is nothing like what you read about him in the press," the Spain international stated at a press conference.
"He is a committed coach and has got the best from every single player. The club was clearly right to hire him.
"He has a goal in mind and he feels at home here. We hope that lasts a long time."
The 49-year-old has guided Real Madrid to one Copa del Rey and one Liga title since taking charge of Los Blancos in 2010.