Two second-half tries to Warriors back-rower Ben Henry saw the Warriors in front 22-18 with 30 minutes remaining but the Broncos fought back with winger Dale Copley scoring two tries in two minutes to give his side the match-winning lead in the 67th minute.
The Warriors attacked desperately through the frenetic dying stages but were unable to engineer a breakthrough against an under-siege Brisbane side, who put aside a disrupted build-up that saw three players demoted midweek for breaking team protocols, to post their first win in four starts.
The result ends the Warriors' own three-game winning run and sees the Broncos leapfrog them into sixth on the competition ladder. Both sides remain locked on 22 points with the eighth-placed Storm, ahead of a chasing pack of four teams - the Cowboys, Dragons, Tigers, and Eels.
Coach Andrew McFadden now faces a difficult test in getting his side back up for next Sunday's blockbuster against competition leaders Manly, and after knocking on the door of a top-four position, their place in the eight could be endangered by consecutive defeats.
"Everything went well for us at the start of the game and we executed really well and got points but it maybe came just a bit too easy for us," he said. "When the opposition pushed back on us we gave up easy points.
"The opposition were clearly very desperate and had to come up with some big plays. They took their opportunities and we didn't. Conceding 28 points tells that we weren't committed to our defence. We're certainly not panicking. We've had tough games and come out on the right side. Tonight we were a bit down in the key areas that we've been priding ourselves on."
A frenetic first half saw the Warriors start the match with the same intensity as they finished last week's 48-0 demolition of the Eels, posting two early tries to Simon Mannering and Sam Tomkins for a 12-0 lead after 10 minutes.
The visitors looked unstoppable as their hard-running forwards and powerful outside backs gained easy metres up the middle and had the Broncos at sixes and sevens out wide.
They were unable to maintain those standards, however, and mistakes and a lack of composure allowed the Broncos to fight back. The Warriors lacked direction and looked sluggish in the face of the host's enthusiasm, despite the return of Thomas Leuluai from a three-month injury layoff, and Konrad Hurrell found himself on report.
After not conceding a point in two hours of football over their past two matches, the Warriors defence finally cracked when Broncos prop Ben Hannant burst over in the 15th minute. The hosts continued to apply pressure and two more tries to Ben Hunt and Lower Hutt-born Jordan Kahu left the Warriors rattled and trailing 16-12 at the break.
The score ebbed and flowed early in the second half before the Broncos rallied again. With Hurrell off the park following a head-knock, they began finding room out wide through the Warriors' fragile and tired right-side defence and Copley was the beneficiary with two tries.
The Warriors gained their composure and a Tomkins break took play back down inside the Broncos 20m zone but, despite their best attempts, were unable to crack the Broncos line.
Broncos 28 (D. Copley 2, B. Hannant, B. Hunt, J. Kahu tries; C. Parker 4 goals) Warriors 22 (B. Henry 2, S. Mannering, S. Tomkins tries; S. Johnson 3 goals).
