"I gave them a spray at halftime ... it didn't work. There is no point coming back here and spraying them again.
"We did our review as usual on Tuesday and we were very honest and the boys copped it on the chin."
The defeat by Newcastle marred a fine run of form that had seen the Eels surge into the top eight and Arthur said the manner of the second-half performance was hard to take.
The Knights scored 32 unanswered points to blow Parramatta's for and against to -90. That's easily the worst of any team in the top 10.
"We brought our points against down to 13 over the last six weeks, it's just an attitude adjustment," he said.
"We don't need to re-invent the wheel or learn how to tackle.
"We know how to tackle. We just have to want to do it. We are playing for pride.
"We know there is a semifinal spot there but it's out of our control.
"What's not out of control is how we turn that performance around and where it takes us it takes us."
- AAP