From the moment Macheda met his new boss in 2007, he knew he wanted to break into the first team in order to benefit from his tutelage every day.
And the 20-year-old striker says the secret to Sir Alex’s success is the way he treats all his players – young or old – equally.
"He has a strong mentality and a winning mentality," Macheda told MUTV in a special Sir Alex tribute programme. "He treats every player on the same level.
"You can be Wayne Rooney or be me – he treats everyone on the same level. That’s great for everyone in the team.
"Obviously there are players who are doing better but if they make a mistake he treats them like he has to. He makes them understand that they have made a mistake.
"To be at Manchester United at my age is not easy so every time I get a game he always tells me what to do. I enjoy working with him – he is a great person because he treats you like you are his son and makes you laugh."
Macheda, who is knocking on the door of the first team again after recovering from a shoulder injury, is in no doubt that Sir Alex is the best manager in the world.
"He has achieved everything," the Italian added. "He is the manager who has won the most trophies in the world. To be at this club for 25 years – he must be special."