Northampton boss Jim Mallinder slammed his side's showing as embarrassing and unacceptable after Saturday's 39-17 loss to London Irish.
It was the Saints' first defeat of the season and a furious Mallinder didn't hold back when asked to evaluate his side's performance.
"There was no intensity there from us, our accuracy in just about everything we did that first 60 minutes was awful," he said.
"Mentally, if you underestimate any team in the Premiership then you will get turned over and that is what happened. Mentally we weren't up for today's game and that showed.
"As a group we are all very disappointed. We embarrassed ourselves.
"The talk in the week had all been about how difficult this game was going to be, how desperate London Irish would be, how we should not be looking to give their outside backs any ammunition.
"We had to get our set piece right and defend with intensity - all those things we talked about didn't happen this afternoon.
"We embarrassed ourselves today, we let ourselves down with a performance that was not acceptable."
London Irish director of rugby Brian Smith praised Jonathan Joseph's display and called for the Exiles centre to start for England in their end-of-year internationals.
"I would like to see JJ get another crack," said Smith.
"He is a class act and his talent is well regarded by the English coaches.
"And with Mike Catt (the former London Irish player and coach) now part of the England set-up, he knows what JJ can do."
Smith complimented his side - who claimed only their second win of the season - for their effort against Northampton.
"It was a big challenge for us because confidence wasn't high," he added.
"The boys really fronted up today. They got no change out of us at scrum time and in the lineout drive and we have a lot of class in the back line."