Porto goalkeeper Iker Casillas admits he regrets not confronting Manchester United boss Jose Mourinho when they were together at Real Madrid.

Mourinho infamously dropped Casillas while in charge of Real.

Casillas recalled: "The arrival of Mourinho was to compete with Barcelona, there were moments of great tension.

"We started to see this madridismo that I did not like, to a limit with which I did not identify myself. And it seems that this motivated a reaction from Barcelona.

"At a personal level the relationship was touched by the previous season and by the third year there were a lot of people that started to stir our relationship.

"This was not good for him or for me, nor for Real Madrid.

"I think that if I could go back in time, I would have taken the bull by the horns and faced Mourinho.

"At that moment I chose to remain silent and I thought that would be the way to honor the values of Real Madrid."