Calvisano coach Marc Delpoux admitted his side did not have the physical presence to compete with Magners League heavyweights Cardiff Blues.
His side conceded eight times on their way to a 56-20 defeat on their home patch in their European opener.
He said: "Cardiff were bigger, stronger, have better organisation, players, structure and more money so what we saw here was the picture of that difference.
"I was happy with the effort in the first half but then we collapsed because we are still not ready to compete at this level for 80 minutes."
Captain Leonardo Ghiraldini scored late in the game to give some cheer for the home fans but the result was the start his side had dreaded and leaves them without a point and likely to be propping up the Pool 6 table at the end of the weekend.