It now appears they will scrap with the Tigers, Dragons and Saturday night's foe Newcastle Knights for the bottom four finals places over the last weeks of the regular season.
Having dispatched the hapless Raiders 40-8 yesterday and put 50 points past Gold Coast a week earlier, the Knights will head to Auckland in sparkling form.
Yesterday's result, coupled with the Tigers' Friday night victory over the Dragons, leaves the Warriors, Knights and Tigers level on 26 points.
The Warriors head the bunch on points differential, while all three clubs have a four-point buffer over the ninth-placed Bulldogs.
Two wonder tries - one a brilliant solo effort from Shaun Johnson and the other created by a James Maloney chip and regather and finished explosively by Kevin Locke - weren't enough to see the Warriors past the determined Broncos.
After coming back strongly through a Shaun Berrigan try and a Maloney penalty to tie the game with 10 minutes remaining, the Warriors had their chances to pull off what would have been a fine victory.
Instead they succumbed to some familiar late-game failings.
Maloney missed a field-goal attempt from a handy position with five minutes remaining, while Johnson saw a booming, angled 40m effort drop just under the crossbar.
Wallace showed how it was done with a composed strike from point-blank range with under two minutes remaining.
Even then the Warriors had a chance to send the match to golden point, however they bungled it badly, with the ball ending up in prop Russell Packer's hands, forcing Maloney into a rushed final field goal attempt that drifted harmlessly wide of the posts.
Darren Lockyer's record-tying 349th match was a mixed affair.
His declining pace was brutally exposed by the flying Locke as the Warriors surged ahead in the first half, but the wily playmaker then exposed Feleti Mateo's lazy marker defence with an inside ball to Matt Gillett that put the Broncos back on top.
Lockyer's late field goal attempt was charged down, denying him the chance of a grandstand finish, but the Broncos recovered the loose ball and Wallace calmly slotted over the winning kick.