"There were some things that we were really disappointed with in terms of the way we played," he said.
"We've got to hold ourselves to a high account because that's what really good teams do and we're not a really good team yet, so we've got to keep striving to become one.
"Opportunities going forward we had a few 12-point plays where we not only squandered an opportunity to score for us but we opened ourselves up on the rebound.
Two goals down, Melbourne started well after the main break with Chris Dawes converting after a strong tackle on Shaun Atley.
But from that point the Kangaroos were utterly dominant, with Jack Ziebell and Atley's goals starting the rout.
Lindsay Thomas, Andrew Swallow and Aaron Black then put North Melbourne clear with majors in a five-minute burst.
Debutant Ben Brown, playing in the No. 50 guernsey, was mobbed by teammates when he kicked his first AFL goal and their sixth in a row.
North was rampant, and even out-tackled the Demons despite dominating possession.
Exemplifying the Demons as a team in transition, last week's hero Christian Salem didn't have a possession until deep in the second quarter and was substituted in the third.