The young Brazilian striker said: "The most difficult thing to face was tactical, as in Brazil I was accustomed to running forward and waiting for the long ball from a teammate.
"Ancelotti asked for a different movement, as I have to go towards the ball and then run into space. It took me a while, but I've got it now.
"I am happy the way my first Italian season went, but Milan were unable to qualify for the Champions League and that made me very angry. Now I want to help my team get back into the competition."
He added: "I haven't changed, but I have grown up and learned what it means to play football in Italy. I can guarantee I'll improve. You haven't seen the real Pato yet."