THE CURTAIN is yet to be drawn on their season, but it appears the fall from grace is now complete.

Last night, North Queensland delivered the knockout blow on St George Illawarra's campaign at WIN Stadium, erasing the need for any mathematical ifs or buts about the Dragons' finals prospects.

Premiers in 2010 and a major contender last season, St George Illawarra were ranked among the heavyweights in the pre-season polls.

But they failed to strike a consistent winning formula and will now miss the play-offs for the first time since 2007.

The old firm of Johnathan Thurston and Matt Bowen eventually proved the difference in a physical and spiteful encounter, with both crossing for second half tries.

North Queensland dominated proceedings for the opening 20 minutes, before overcoming a tenacious resurgence from the Dragons to recommence their dominance at the hour mark.

Despite the loss and ultimate finals execution, Dragons coach Steve Price was finally given something to smile about by his side's performance. With the odds stacked against them, the Dragons were able to post one of their better performances of the year. Again, it was their failure to ask enough questions of the opposition defence which cost them.

Daniel Vidot and Ricky Thorby were both sin-binned in the 54th minute following an altercation between James Tamou and Matt Cooper. The dispute was sparked after the NSW prop palmed Cooper's face in a tackle.

The Cowboys were at their menacing best early on, with wrecking balls James Tamou and Matt Scott making easy yardage down the middle of the Dragons defence.

Three consecutive sets inside the Dragons' 20-metre zone created ominous signs early for the largely 9245 pro-St George Illawarra fans who turned out at WIN Stadium.

Inevitably it was winger Ashley Graham who pounced on their easy opportunities six minutes in, before another to Kane Linnett eight minutes later.

By contrast, the Dragons were stale and meek early on. When they weren't copping a battering from the Cowboys attack, they were struggling to formulate their own.

But the red and whites mounted an unexpected comeback midway through the first half to reduce the advantage to 18-16 at the break.

First, Ben Creagh burrowed his way through the defence in the 26th minute to get on the board.

Creagh then went from hero to villain in an instant after fumbling the ball on the return kick, allowing Linnett to cross for his second the following play.

Mitch Rein's intuition in attack handed the homeside another four-pointer in the 33rd minute, before a slick Jamie Soward long ball put Daniel Vidot over five minutes later.

It was a reversed sequence of events in the second stanza, with the Cowboys storming home from a 22-18 deficit.

Dragons prop Dan Hunt provided his side a good foundation for the half with his try off the back of a Matthew Scott penalty for late contact on Jamie Soward.

But Thurston and Bowen anchored a hard-fought win with individual tries in the 61st and 63rd minute.

Last night's result means the battle for two remaining play-offs spots is essentially down to three, with Brisbane, Wests Tigers and Canberra now locked on 26 points.

Gold Coast and Newcastle are outsiders on 24 points, while the Dragons are now languishing further behind the eight-ball on 22 points.

The win boosted the Cowboys to fifth on the ladder, and what's more saw Neil Henry's side go one step closer to being tagged official competition spoilers.

NORTH QUEENSLAND 32 (K Linnett 2 M Bowen A Graham J Thurston tries J Thurston 6 goals) bt ST GEORGE ILLAWARRA 22 (B Creagh D Hunt M Rein D Vidot tries J Soward 3 goals) at WIN Stadium. Referee: Adam Devcich, Ashley Klein. Crowd: 9,245.