A deflated Josh Hannay lashed the Cowboys for throwing away an "unloseable game" to the Rabbitohs in the final minutes by producing some "bonehead" moments.
The interim coach said he's fed up with "premiership-winning" speeches from the team when their performances are anything but.
The 31-30 loss, decided by an Adam Reynolds field goal, was in many ways a stark improvement on last week's defeat to the Titans.
Star winger Kyle Feldt made some costly errors with four missed goals and a crucial conceded penalty that allowed Reynolds to level the scores after he shanked a conversion a minute earlier.
"I'll have to watch that last five minutes again, but there were a number of individuals that just came up with some bonehead plays. Just schoolboy, bonehead, not doing their job," Hannay said.
"It wasn't one or two - there were a few there. Five to go, just ... wow. It was just really, really bad."
Match Highlights: Cowboys v Rabbitohs
Hannay admitted he was at a loss to explain how North Queensland went from almost certainly securing an upset win to being pipped.
He gave the side a spray last week - saying they did the "club and jersey a disservice" - and now has to figure out his response to a different kind of capitulation.
Relive the final moments of Cowboys v Rabbitohs
"There's guys in there apologising and [are] upset. We're premiers at saying the right thing as a group," Hannay said.
"I've heard us say the right thing for too long but ... I'm over us saying all the right things and not doing it correctly. They say some wonderful things, but man, talk about not backing it up.
Clutch Reynolds wins it for South Sydney
"They say losing is a habit but sometimes you lose because the opposition are too good. Tonight, that last five minutes was just unbelievably dumb and poor by individuals in our team.
"I don't put that down to losing being a habit for us. I just put that down to just guys not doing their job. It's that simple."
Up until the end, Cowboys captain Michael Morgan looked like making the headlines for his outstanding effort to rebound from a subpar performance last round.
The halfback, in his second match back from a long-term shoulder injury, scored a double and was much improved in defence.
"That's how champions respond, isn't it," Hannay said.
"Everyone knows he wasn't himself last week. You had to see him around training to understand how devastated he was. It wasn't something that he was able to just brush off.
"Tonight was Michael Morgan at his best. Running the football, taking the line on, his contact was a lot better. He led by example.
"If there's a positive to take out of the night, it's certainly the performance of our skipper."
Hannay will persist with Feldt as goal-kicker for next round's clash with Newcastle, who North Queensland's last win came against in round seven.