Broncos 26 Knights 6
Brisbane weakened Newcastle's tenuous grip on a top-eight berth, but their win may have come at heavy price.
Star centre Justin Hodges is in danger of missing the remainder of the NRL season after limping to the bench six minutes into the second half with his third hamstring injury of the season.
The Knights, now level with ninth-placed South Sydney with two rounds remaining, also lost players.
Junior Sau went off early with an ankle injury, and Matt Hilder was taken by ambulance to hospital with a nasty gash after a head clash with teammate Joel Edwards.
But even when the Knights had their full complement they struggled to contain the third-placed Broncos, who would have won by more if not for their own wastefulness.
They were lucky to get on the board first when video referee Steve Clark needed double figure looks at replays to award Peter Wallace a try.
But there was no doubt when Sau made a defensive blunder and Hodges crossed for 8-0 after 14 minutes.
It may have been karma for the first try when what looked a legitimate Josh McGuire try was pulled up for a forward pass, and Chris Houston was sin-binned when he denied Jack Reed a four-pointer by taking out the burly centre without the ball.
The opportunity to put the undermanned Knights to the sword instead became Newcastle's invitation back into the contest as Akuila Uate cut the deficit to two points after Gerard Beal spilled a clearing kick.
The Knights pushed hard after the restart with some strong carries and looked like they had locked it up, only for skipper Kurt Gidley to be held up over the line after a dazzling 20m run.
That signalled the beginning of the end for the Knights.
Jharal Yow Yeh took an intercept 90m only minutes later to push the Broncos out by 10 in the first of three second-half Brisbane tries.
The others were scored by Alex Glenn and Ben Hunt.
- AAP