After needing a draw in the last minute of the regular season at Penrith to claim the last berth in the finals series — and a staggering two-try comeback to snatch last weekend's preliminary final — this time the Warriors relied on resolute defence to cling to a 34-32 win and become the first team to win the under 20s premiership from outside the top four.

The only team to win multiple titles since the competition was launched in 2008 – this championship exceeded their predecessors in 2010-11 by avenging last year's loss to Penrith.

Battling a Queensland-like climate throughout an energy-sapping encounter waged in 30-degree-plus heat — the Warriors also had to defy the loss of  hooker Kurt Robinson, a setback that stressed their interchange bench.

Robinson failed a concussion test after tackling rampaging prop Joe Ofahengaue in the 18th minute, reducing their rotation for more than an hour in an atmosphere that forced the Warriors players into the shade provided by the stand at every opportunity.

Fortunately Robinson's replacement at dummy half, centre Nathaniel Roache, provided a more than adequate stand-in — especially when he broke the defensive line from a play-the-ball to set up Tuimoala Lolohea for a crucial try four minutes from the break.

Lolohea's try gave the exhausted Warriors an important breathing space buffer three minutes after Solomone Kata completed his hat trick via an excellent cut-out pass from Mason Lino.

Critically, the France-bound playmaker and co-captain persevered after adding a shoulder injury to an existing knee problem and although his tactical kicking was not up to its usual high standards, he still kept the Warriors going forward in tandem with Lolohea.

The Warriors, who knocked out the Sydney Roosters, minor premiers Newcastle  then Parramatta — with a stunning comeback in last weekend's preliminary final, were denied a try in the third minute minute when video referees Ashley Klein and Luke Patton debatably ruled that Roache deflected a Lolohea bomb forward before the second rower, Michael Ki,  crossed unopposed.

Their luck changed in the seventh minute when Kata opened his treble despite referee Chris Butler suspecting he had stripped the ball in a double tackle on Duncan Paia'aua.

There was nothing contentious about the centre's second when he bent to pick up an Adam Tuimavave-Gerrard nudge to the right hand corner.

Brisbane, seeded second after the regular season, barely mounted a viable attack in the opening quarter but got on the board through birthday boy Jayden Nikorima who set up fellow impact player with just his second touch of the ball.

Nikorima was a constant threat sniping from the ruck, and only desperate defence and a double movement prevented him reducing a 22-6 half-time deficit.

Although Ken Maumalo scored soon the resumption off another excellent ball by Lolohea and co-captain Sam Lisone pushed the advantage to 28 points, the undermanned Warriors were always likely to be susceptible on the run home.

A quick-fire double by wing Paul Byrnes gave the Broncos hope heading into a frenetic final quarter and when Nikorima's brother Kodi and right wing Jack Tuttle trimmed the margin to a converted try.

The Warriors somehow managed to defend four successive sets but their resolve was finally broken when Jayden Nikorima dived over with two minutes, 13 seconds on the clock.

Needing to land the angled conversion to push the contest into golden point,  Nikorima's birthday celebrations were soured when the ball flew agonisingly wide,  leaving the Warriors to survive another 45 seconds, a timeframe that resembled an eternity.