Inter thrashed Sassuolo 7-0 on Sunday.
"No, I didn't expect Mazzarri to have quite this impact," Moratti said.
"He's done brilliantly because he's a hard worker and he's instilled the same sense of joy and duty that he has in everyone else. Hopefully that will continue.
"The players seemed proud to be playing for the shirt. When you win you feel you're part of an ideal.
"We've spent intelligently, bringing in lots of youngsters who have come in for criticism but are showing how talented they are."