North Queensland coach Todd Payten is urging confidence from Robert Derby as he recalls the rough diamond winger for a must-win NRL clash against St George Illawarra.

Derby had a tough night in his last NRL game but comes back at the expense of Jaxson Paulo with the season effectively on the line.

Against Canterbury a fortnight ago, Derby made three errors and found himself caught infield as debutant Jethro Rinakama scored what proved Canterbury's game-winning try.

After the game, Payten said his team's errors were causing him to lose sleep, and Derby has made the fourth-most of any player in the league this season.

But the coach has been working with Derby in his week out of the 17 and wants the 23-year-old to draw strength from the positive attacking moments he's had this year.

"Be confident in that ability. We're backing him, his teammates back him," Payten said.

"We've spoken a couple of times about staying in the moment and concentration but we've also spoken about a couple of technical things and got some work done there around how he carries the ball."

The Dragons and Cowboys are both already unlikely to make the finals this season but a loss in Friday night's game would make it almost impossible.

Payten insisted the Cowboys were still targeting a top-eight berth.

"It hasn't been spoken about but it's still our intention. It starts tomorrow," he said.

Jasper Bruce - AAP