The Raiders registered their sixth straight victory with a tense 18-16 win against a Broncos side who will miss the finals for the first time since 1991.
But Canberra had to withstand a barnstorming Broncos finish as late tries to winger Jharal Yow Yeh and utility Matt Gillett brought the 38,872 crowd alive.
The home side almost pulled off a miracle but a desperate Terry Campese knocked down an attempted off-load by Brisbane prop Scott Anderson to Sam Thaiday a few minutes from fulltime as Canberra clung to an 18-16 lead.
A loss would have left the Raiders' finals fate hanging on the result of Sunday's clash between St George Illawarra and South Sydney.
Brisbane's task of not just winning, but winning by 15 points, was always going to be massive for the injury-weakened side missing skipper Darren Lockyer and playing on tired legs.
The equation was out of reach at half time following tries from bombs by Canberra winger Daniel Vidot, who finished with a double, and fullback Josh Dugan, four minutes apart for a 12-0 lead.
Young Brisbane hooker Andrew McCullough gave the crowd a glimmer of hope when he dummied and stepped inside two Canberra defenders in the 28th minute.
But when Corey Parker missed a simple conversion from in front, there was a feeling it was not going to be Brisbane's night.
Brisbane blew three or four tries in the first half, twice when kicks for support players were way too heavy.
Canberra's massive forward wall of Tom Learoyd-Lahrs, David Shillington, Scott Logan and Dane Tilse kept punching up the middle and Dugan and Campese were outstanding behind their bruising pack.
"We fell away at the end," said representative prop Dave Shillington after Canberra led 12-4 at half time.
"We gave them a few chances to come back and beat us."
The loss was Israel Folau's 91st and last game rugby league, at least for the next four years, with the youngster headed to the AFL.
Folau, who tried hard to score a farewell try for fans, ended his time with Brisbane with 37 tries in 38 games.
Canberra last played finals in 2008 under Neil Henry.