Brisbane had two men sin-binned as Cronulla came from behind to win 24-16 and scrape back into the NRL's top eight with one round to play.
Enforcer Tom Flegler's high shot on Jack Williams earnt him 10 minutes in the bin in the first half, the Sharks scoring twice to reclaim the lead after Brisbane had held a 10-6 advantage.
The Broncos' second-half surge then stuttered when Brendan Piakura was binned and reported just six minutes into his debut for a late hit on influential halfback Braydon Trindall.
Cronulla weren't able to put Brisbane away though, Anthony Milford showing signs of his best as he prepares to leave for South Sydney and fullback Tesi Nui scoring twice for the hosts at Suncorp Stadium.
Still down a player, emerging centre Selwyn Cobbo was narrowly put into touch before a flying Herbie Farnworth's pass to Corey Oates missed the target as the Broncos looked to make it a two-point game in the final six minutes.
Try-scorers Trindall, Jesse Ramien and Sione Katoa were all standouts for the Sharks, while Matt Moylan hung tough in defence to defy Brisbane's last-gasp efforts.
Ramien could miss some time though, also reported for a late shot on Herbie Farnworth in the first half.
It puts Josh Hannay's side two points clear of the Gold Coast and ahead of Canberra on differential in the battle for eighth ahead of their last-round date with Melbourne.
Brisbane meanwhile stay stuck on just seven wins despite some encouraging late-season form.
Milford was electric for Brisbane, setting up Niu's second try with a trademark line-break.
Niu had earlier side-stepped his way to the line as Brisbane set up an early lead.
But Ramien scrambled to ground the ball immediately after Flegler was binned, then Connor Tracey finished off a zig-zagging run from Katoa who had scored the game's first try after just three minutes.
Trindall then created a buffer, barging over early in the second half before they hung on to secure a 10th NRL win this season with the recovering Andrew Fifita watching on from the sideline.
