Donnarumma fell out with fans when stalling on signing a new deal 18 months ago.
The young keeper admitted it was “difficult" but has claimed he never “feared" them.
“It's difficult to play when the fans are against you, when they boo you," he said. “San Siro is San Siro, but I was never afraid.
“I knew who I am, I knew what I could do. I had zero fear. It all seems normal to me; I think that's what keeps me at this level.
“I do things, saves, and they seem normal to me. And then I like to command, I am happy to do it."