"It is enjoyable (working under Ferguson). Sometimes you get a little bit nervous around him because obviously he is Sir Alex. You don't know what to say or do sometimes," Berbatov told skysports.com.
"He is a really nice guy. He speaks with you when necessary, or sometimes he raises his voice to make his point clear."
The Bulgaria striker added: "I am still working on everything. Everything is new to me. I am still working on my training sessions and my performance in games.
"But I think, for now, things are going according to plan. I am working hard and fighting for my place.
"Sir Alex is in charge and you must prove to him in every training session and every game. And I am trying to do that."