Kaka has opened up about the "respectful but complicated" relationship he had with Jose Mourinho during his time at Real Madrid.
Former Brazil star Kaka rose to prominence after joining AC Milan in 2003, winning Serie A and the Champions League as well as being named FIFA World Player of the Year in 2007.
His standing in the game led to Madrid making Kaka one of their 'Galacticos' in 2009, but – despite winning La Liga and Copa del Rey medals under Mourinho – he failed to replicate the same form that made him such a sought-after attraction in Milan.
Kaka, who retired in December 2017 having last played for Orlando City, accepts that, despite his best efforts, he was unable to fit in under Mourinho at the Santiago Bernabeu.
"In 2009, I accepted the proposal of Real Madrid, but I was completely destroyed there because I could not give what I had given Milan, I was completely lost," he told UOL Esporte.
"Jose Mourinho was a difficult coach for me and we had a respectful but complicated relationship.
"When I thought he would give me a chance, I couldn't prove to him that I was in good shape.
"I trained, I fought and I prayed a lot, but having not received the confidence of the coach, I realised that I could not work with him.
"The joy I had was to receive a message when he left Real Madrid and said that I was one of the most professional players he worked with."
Kaka, a 2002 World Cup winner with Brazil, departed Madrid in 2013 to return to Milan.