Gold Coast fullback Keano Kini conjured up the attacking play of the season to sink Brisbane 28-23 and leave the premiers' title defence in ruins.
A 73rd-minute Adam Reynolds field goal appeared to have taken the Broncos to victory at Suncorp Stadium on Saturday, before Kini, from 55m out, chipped ahead and snatched the ball from Reece Walsh's grasp to race away in the 77th minute.
Kini then saved a last-gasp try attempt by the Broncos when he knocked the ball dead to secure one of the club's great wins.
The Titans showed incredible resilience to turn the Broncos away at the death
Brisbane have now lost five matches in a row and sit in 11th position.
The Broncos were wearing their all-black mental health jersey, the same one they donned against the Titans last year in round 14 when a win kick-started a 10-2 finish to the season and a run to the title.
