The two nations meet on Sunday in the round of 16.
Calzona said: "Once England produce a great performance as a team at this tournament they will become unbeatable. They have a top-quality squad, the best squad of these Euros. They have physicality, technique and creativity. They were even able to leave quality players at home because they have so much to pick from.
“We need to make the most of any weak points they have, but we must always be cautious because this is a team that can punish you at every moment. If we talk about the quality of the two squads it is clear that we are inferior. They are worth 1.5billion euros. We are worth about £150million euros. So we are 10-times less than them.
“I’m lucky because I have a very focussed team who want to play offensive football but be defensively sound. I trust my players because they have given me a lot of satisfaction in the way they have played and behaved. I trust them 100 percent that they will play a great match.”