Giaccherini has arrived from Juventus this month.
Di Canio enthused: "You have to change your mentality completely. But I was sure about his attitude and desire to come to England. When you sign a foreign player I want to know if he loves English football and if he has a desire to understand English football and integrate himself in English life.
"He's a fantastic lad and will be one of the best players in this league. He's a very humble guy but he is one of the best players in one of the best national teams in the world. He's a still a bit behind and he's a bit heavy in his legs right now but in the future he will be a crucial player."