The Sydney Roosters narrowly missed out on leap-frogging the Warriors and grabbing fifth spot on the ladder for the start of the finals as they outclassed the Cowboys 18-8.
Needing to win by 16 points to get fifth spot on for-and-against, the Roosters fell agonisingly short.
But they rounded off their preparations for the big games in fine style against a struggling Cowboys side.
The Cowboys spent much of the opening stages camped in the Roosters' quarter and were rewarded when fullback Matt Bowen produced one of his trademark darting runs from close quarters, beating three defenders in quick succession to dive over in the corner.
In a scrappy first half, the Roosters replied in the 29th minute through a smart piece of work by replacement hooker Mitch Aubusson.
Aubusson twisted in a tackle and passed the ball to centre Shaun Kenny-Dowall, who dived over.
Todd Carney added the extra to edge the Roosters ahead 6-4 and they would have taken a bigger lead to halftime but for a dreadful error from halfback Mitchell Pearce.
Pearce darted through the defence four minutes from the break – dived for the tryline - and dropped the ball.
Video referee Chris Ward had several looks at the incident before ruling no try.
The Roosters struck a vital blow immediately after the resumption when quick hands along the backline put Kenny-Dowall into space.
The tall centre was rounded up two metres from the line, but reached out with a long arm to score, Carney's conversion extending the lead to 12-4.
North Queensland made a game of it midway through the half when five-eighth Grant Rovelli put veteran centre Ty Williams – playing his final game for the club – over with a sweetly-timed pass.
John Williams again missed the conversion shot but the Cowboys were back in the hunt at 12-8.
The Roosters sealed an impressive win when Pearce backed up prop Nate Myles to score 11 minutes from the end.
Sydney Roosters 18
Tries: Kenny-Dowall 2, Pearce
Goals: Carney 3
North Queensland Cowboys 8
Tries: Bowen, T.Williams