Matheson Johns scores in the corner for the Dragons against the Cowboys in the Holden Cup finals.

A try to winger Matheson Johns three minutes into golden point extra-time has seen St George Illawarra score a stunning 34-30 win over North Queensland in their Holden Cup Qualifying Final at Suncorp Stadium on Friday night.

The Dragons fought back from a 12-point deficit early in the second half to hit the front 26-24 before two tries in the final three minutes saw the Cowboys take back the lead and then Field score wide out to level the scores at 30-all, mirroring exactly the score between the two teams when they met back in Round 12.

Field had a chance to win the game at the end of 80 minutes but his conversion attempt from the sideline swung across the front of the posts and they reset for golden point extra time for the first time this season.

The teams traded sets to start extra-time before a bust by the Dragons put them on the attack and classy fullback Matt Dufty put Johns over out wide, Johns showing great skill to drag in the pass and put it down before going into touch.

North Queensland used their captain's challenge to send the decision for video review but replays showed Johns clearly grounding the ball and in the process earning his team a week off next week.

The Cowboys will now have to wait to see their next opponent, due to play the winner of the Wests Tigers v Parramatta clash on Sunday.

Seemingly unperturbed by the egg-throwing incident that had embroiled the club in the 24 hours prior, Cowboys fullback Kalyn Ponga put on a complete display of his incredible talents early in the game.

His opening kick-off went dead in-goal and he laid on a try for centre Enari Tuala and converted from the sideline, all in the opening two minutes.

The exciting Cowboys backline looked ready to cut loose but the Dragons worked their way back into the game, skipper Patrick Herbert showing just what a promising future he has in the game with an individual effort to score in the right-hand corner, Field converting from the sideline to level the scores.

North Queensland try-scoring freak Gideon Gela-Mosby was brought down inches short of the line after 13 minutes and then the Dragons hit the front three minutes later when Izaac Thompson soared high above the Cowboys to snare a Jack Payne cross-field kick and struggle the Steeden to the turf.

Ponga was prominent again in the 25th minute with a cut-out pass to put Marcus Jensen across for his 25th try of the year, the 18-year-old landing the conversion from the opposite sideline for a 12-all scoreline.

Struggling with the greasy conditions, the Dragons made a number of errors coming out of their own end and eventually it told, with clever Cowboys hooker Brandon Smith pushing past four defenders to get the ball down next to the posts six minutes from half-time.

Ponga showed great hands to tip on for Marcus Jensen to score his second try of the night and 26th of the season early in the second half but the Dragons refused to go away.

Keelyn Tuuta-Edwards and Herbert scored, Field was denied by a super effort from Ty Carucci but when the fleet-footed five-eighth scored with 17 minutes to play the Dragons led 26-24.

It was a lead they held until three minutes from full-time when Nathan Traill converted a long-range Cowboys break into points before Field rescued his team in the final seconds of regulation.

St George Illawarra Dragons 34 (Patrick Herbert 2, Jai Field 2, Izaac Thompson, Keelyn Tuuta-Edwards, Matheson Johns tries; Jai Field 3 goals) def. North Queensland Cowboys 30 (Marcus Jensen 2, Enari Tuala, Brandon Smith, Nathan Traill tries; Kalyn Ponga 5 goals) three minutes into golden point extra time. Half-time: Cowboys 18-12.