Respectable losses won't cut it for interim Cowboys coach Josh Hannay, who urged his young team to "grow up" and "do your job in big moments" after letting victory slip.

North Queensland maintained the improved effort they've displayed in recent weeks but lost 14-12 to the undermanned Raiders as execution - particularly their last-tackle options - let them down.

Hannay, whose head coaching record now stands at 0-2 after he took over from Paul Green last round, said he was feeling "torn".

"We keep shooting ourselves in the foot. So one part of me is immensely proud, the other is immensely frustrated and angry," Hannay said post-match at Queensland Country Bank Stadium.

"And at some point as a footballer, no matter what level of experience you are, you need to grow up and you need to do your job in big moments particularly.

"That's three weeks straight I'd say our effort has been first-class. And three weeks straight inexperience, just individuals not doing their job when the game comes their way [has been the problem].

"For the most part, they all did their job spectacularly well. But you've got to do it for 80 minutes ... You can't clock off. We've got to keep working really hard with these guys."

Match Highlights: Cowboys v Raiders

Hannay admitted he made an "error in judgement" when he used his eighth and final interchange to replace prop Francis Molo with John Asiata in search of points at the 70-minute mark.

Asiata, who returned from an MCL injury that had sidelined him since round four, was helped off after another suspected knee problem with seven minutes remaining, leaving the Cowboys with 12 men.

The skilful prop stunningly came back on the field for the final few sets but he couldn't help the team secure a last-gasp win.

"I thought Canberra were out on their feet and I went for the killer blow," Hannay said of the interchange decision.

He saw one positive in the unfortunate circumstances.

"We defended our line with 12 men and there's been times this year where we haven't shown a capacity to defend it with 13," he said.

"Defensively, we were enormous. We did identify key individuals - Jack Wighton and Josh Papalii and guys like that - who carry the ball so strongly, and I thought we did a heck of a job on those guys."

While Asiata returned to the field, Hannay couldn't confirm whether the 27-year-old had escaped a lasting injury.

"I guess it's a good sign that he was able to go back out and I thanked him for that effort, but at this stage it'd be too early to tell the severity of what he's done there," Hannay said.

"I thought we benefited from having both him and Jordan McLean back [from a calf injury].

"I was really strict with Jordan's minutes, I kept him to two 20-minute stints to make sure that we're doing the right thing by Jordan."