Kaka, former Madrid star and Brazil icon has blamed Manchester United manager Jose Mourinho, for denying him success at Santiago.
Kaka who retired in December said Mourinho is very difficult to work with.
He was signed for £56 million in the summer of 2009, a year before Mourinho joined the club.
In an interview with UOL he said "I accepted the proposal from Real Madrid, but after that move I was completely destroyed, because I couldn’t replicate what I’d done for Milan.
"I was totally lost. In Italy, everyone had loved me, but in Spain they all wanted me to just leave.
"Plus, Jose Mourinho was a difficult coach for me to work with. When I thought he might give me a chance, it never happened.
"I didn’t get the chance to prove my form to him. I trained hard, fought and prayed so much, but without the coach having faith in me, I realised I couldn’t work with him.
"I was so happy after leaving Real Madrid and returning to Milan, especially after Mourinho said I was one of the most professional players he had ever worked with."
