The Canaries were 3-0 down by half-time and a second-half double by Adam Idah was no more than a consolation.

"Six goals, the more I say it, the worse it sounds. It is embarrassing," McLean told BBC Radio Norfolk.

"It was inexcusable. It was the worst (performance) since I've been at this club that I've been a part of. In all aspects, it was a shambles.

"People came to support us and that's what we gave them. We don't deserve the support that they've given us. Unforced errors, mistakes, you name it, everything."

Norwich began the Championship campaign well, taking 10 points out of a possible 12 in their opening four games.

But David Wagner's side have lost three of their last four, dropping them to eighth place in the table and eight points behind the top two, Leicester City and Ipswich Town.

"If teams have come up with a plan to play against us, then we need to try and combat that," said Scotland international McLean, who agreed a new contract to run until 2026, with an option for a further year, earlier this month.

"The start of the season has gone now. We had a couple of decent results, people got carried away - forget that, there's work to be done. That was not acceptable."

Norwich are away to Fulham in the EFL Cup on Wednesday before hosting Birmingham City on Saturday in their next Championship fixture.

And McLean says the squad need to "face up to the criticism" and learn lessons quickly.

"I'm not questioning the character in there (in the dressing room) but after that, there's lots of things to be questioned," he added.

"We need to put things right quickly, start winning and show how much we care. We've let everybody down."