Crowd trouble has marred the Bulldogs' 29-22 victory over NRL ladder-leaders Brisbane at Telstra Stadium on Friday night.
A "large firework" detonating in the northern grandstand in the 69th minute was the main talking point despite the Bulldogs running out five-tries-to-four victors, jumping from 10th to fourth on the congested league ladder.
A Telstra Stadium spokesman said no one was injured by the explosion that sent a shudder around the ground.
He said police were investigating the matter with stadium security scouring video footage in a bid to identify the troublemakers.
The stadium spokesman said sniffer dogs and bag searches were conducted at the ground, admitting that the crowd members "went to some elaborate lengths" to smuggle in the firework.
An NRL spokesman tonight said it was a "police matter".
"We don't even know if it was football fan as yet. If it is we will consider a ban," he said.
Canterbury supporters were involved in ugly scenes during the Bulldogs' 2004 round three 35-0 loss to the Sydney Roosters at Aussie Stadium.
The NRL threatened to deduct four competition points from the Bulldogs for any repeat crowd trouble, but that expired at the end of 2004.
The incident took the shine off a polished performance by the Bulldogs who moved to a 9-1-8 record with their third straight win and fifth in six games.
"The last three weeks have been pretty pleasing, our commitment has been good... tonight was pleasing because Brisbane are on top of the comp but we have a long way to go - we need to keep improving," Bulldogs coach Steve Folkes said.
"There's still a lot we have to get right."
Brisbane remains on top of the NRL ladder on 14-4 after suffering only its second loss in 14 games.
After trailing 22-10 after 51 minutes, Brisbane fought back to even the ledger 22-22 in the 60th - Broncos skipper Darren Lockyer setting up tries to both David Stagg (54th) and Tonie Carroll with short clever passes.
Lockyer was at it again in the 64th, grubbering through for centre Shaun Berrigan, but the league's try-scoring leader failed to ground the ball properly and was denied by video referee Graeme West.
Adding to Brisbane's frustration, halfback Brent Sherwin threw a huge dummy and waltzed over under the posts in the 68th minute to make it 28-22 before the firework detonated.
Bulldogs five-eighth Braith Anasta then put Brisbane away with a 77th minute field goal.
"For us to come back after they got back to 22-22 was a terrific effort. They are the benchmark team in the competition so we've got to be happy with our performance... but we need to keep working hard on our game," Folkes said.
Brisbane coach Wayne Bennett said: "Maybe if Shaun grounded the ball in-goal there it might have been a different game - he didn't ground the ball and we lost our way a bit after that.
"We lost more of our structure and control of the game, making errors that cost us dearly. We didn't do a whole lot wrong...but the mistakes we made they capitalised on."
Carroll said Brisbane backed itself to kick on with victory after levelling the scores.
"When we got level, there was a good vibe in the team. Everyone was pumped up and then a couple of things went wrong and we dropped our heads... the bounce of the ball didn't go our way."
Adding to Bennett's pain, Justin Hodges and Corey Parker were placed on report for a 78th minute tackle on Bulldogs lock Tony Grimaldi.
