Five-eighth Gayle Broughton orchestrated the 24-6 halftime lead that the Broncos rode to victory in hot conditions on Sunday afternoon.
Their ninth straight win confirmed a grand final match-up that had felt inevitable for weeks, given Brisbane and the Roosters' clear status as competition frontrunners.
It marks the Broncos' first appearance in the decider since winning the NRLW's first three premierships between 2018 and 2020, when the league had only four teams.
Co-captain Ali Brigginshaw was relieved to have finally made it back, after the Broncos were eliminated in grand-final qualifiers in three of the past four years.
"We've worked so hard over the years and we've had the team and we've just fallen short," she said.
"A few of us just looked at each other and thought, 'Finally, we got here'."
Ominously, the Broncos were well below their best despite the one-sided result.
Brisbane completed at only 59 per cent, and the league's best player Tamika Upton had a quiet game by her lofty standards.
But Brisbane's goal-line defence was once again superb, the Broncos now the only team in NRLW history to leak six points or fewer in four straight games.
"I'm just proud of how we defended," Brigginshaw said.
"The attack wasn't quite on, there were quite a few errors. It was extremely hot out there.
"But we'll hold our heads high and enjoy getting through that hump and then prepare for the Roosters."
Two of Brisbane's four first-half tries came after ex-Olympian Broughton targeted Sheridan Gallagher with her kicking game.
Gallagher had a nightmare on the right wing for Newcastle, dropping kicks that helped Kerri Johnson and then Lauren Dam score from point-blank range in the corner.
Upton got one over her old side, grabbing a Broughton flick pass on the 30-metre line and dancing past rival fullback Botille Vette-Welsh for a three-score lead.
The Knights were clunky despite some good opportunities.
"You don't want to be knocked out at this time of year. It's gut-wrenching, to be honest," said coach Ben Jeffries.
"You just can't give that sort of start away - 24-0, you're trying to climb it back. There were probably too many missed tackles, offloads. In this heat, it zaps you."
The Knights' only try came when Jules Kirkpatrick dived over from dummy-half at close range, much the same way Jada Ferguson had scored Brisbane's first after four minutes.
The result appeared beyond doubt when Kirkpatrick coughed up the ball in the red zone and into the grasp of superb Broncos rookie Shalom Sauaso.
Sauaso (126 run metres) shifted left to Mele Hufanga and Johnson, who had her try-scoring double on the back of a 90-metre tear.
8°C