Mourinho has suggested that Pereira's decision to leave Old Trafford on a temporary basis proved that the Brazilian was not ready to play for United.
However, Pereira - who has made just two starts for United since moving to the club in 2014 - has said that he must start to prioritise his own wishes, rather than spend another season as a backup option for the Premier League outfit.
The 21-year-old told AS: "I could see it from a negative side and think he was angry with me, but I was always very good to him. We were always honest with each other.
"I think of the positive - if I were not a good player, he would not have said anything in the press, he would have let me go and that's it. I think he was worried because I left. I have to think about myself now."
Pereira - who has already made seven La Liga appearances for Valencia - has revealed that he wants to remain at the Mestalla until next summer.