Raiders coach Ricky Stuart said officials "got it 100 per cent wrong" in not sending Reece Walsh off for a headbutt on Hudson Young.
The incident came mid-way through the second half and would turbo-charge what became one of the most dramatic finals games of all time.
In the end, a Ben Hunt field goal in golden point saw the Broncos into the preliminary final after 94 minutes of football, with Canberra looking to have done enough to seal victory on several occasions.
On the incident between Walsh and Young, which saw both men sent to the sinbin, Stuart said it would have been a different outcome if the roles were reversed.
"They've set a precedent now, you're allowed to headbutt," the veteran coach told reporters after the game.
"If Joe [Tapine] or Hudson had have used their head on Reece Walsh, what do you think would have happened to them?"
Despite his disappointment at the decision, and the result, Stuart acknowledged the classic contest that the teams put on.
"Let's not make it about that," he said.
"It was a wonderful game of football. It was an unbelievable spectacle for rugby league.
"They got it 100 per cent wrong, but we shouldn't make it about that because it was an unbelievable promotion of the game itself."
Having been up by 16 points with 15 minutes remaining, the Raiders could have been forgiven for thinking they had one foot in the preliminary final.
Unfortunately for them, Walsh came back a man possessed following his 10 minutes in the bin, scoring one try, setting up another, and kicking a 40-20 to help them score again.
With the clock winding down, it was a Reece Walsh field goal attempt which drew the game-tying penalty in front of the posts after Zac Hosking took out his kicking leg.
Canberra will now host the Sharks in a semi final next Saturday, having to back up from their energy-sapping effort off a six-day break.
"If you're not hurting right now, you shouldn't be doing the job," Stuart said.
"We've got to dust ourselves off and go again. We've won games like that this season too."