Mancini has criticised Nasri publicly this season.
Speaking to The Times he said: "I didn't take it the wrong way. I agreed with him.
"I knew. Sometimes I don't need him to tell me because I'm professional. When I go home, I watch the games again.
"I know if I've played well or if I've played s*** and for eight months I wasn't good.
"I understand what the manager was saying, because it must be frustrating when you have a quality player and he doesn't perform and you don't know why because you try to play him there, play him there, but he still doesn't perform.
"So at some point you have no choice but to put him on the bench and you go to the press to try to get a reaction. And it worked.
"Before, I wasn't very good at accepting public criticism. But he (Mancini) just wants the best from his players on the pitch because he has to win. If he doesn't, he gets fired."