Few had heard of the striker when he made his Premier League debut off the bench against Aston Villa at Old Trafford in April.
But after netting a spectacular injury-time goal to seal a 3-2 win for the Red Devils, before repeating the trick in a 2-1 win at Sunderland six days later, the prodigy had made international headlines.
Macheda went on to make a further three appearances as Sir Alex Ferguson's side went on to regain their league title, including starting the FA Cup semi-final defeat to Everton on penalties.
But having been called up to the Italy U21 side - named the Azzurrini - former Chelsea striker Casiraghi has slammed the youngster's mentality, insisting the starlet must display more professionalism if he wants to achieve full international honours with the 2006 World Cup winners.
“He needs to grow a lot, both on the pitch and off it, if he wants to remain a part of this squad,” he said.
“As a player he has many qualities, but they are yet to be expressed fully. If he wants to be a football player, then that is a fun job, but he needs to learn to be a real professional.
“At the moment, that is not the case with Macheda. I say this above all in his own interest. An 18-year-old boy has to throw himself around and give himself completely to the case."
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