Teetering outside the top four and at risk of missing the finals for the second straight season, Brigginshaw stood up to help Brisbane to their third win of the year.
The win kept Brisbane fifth on the ladder, two points outside the top-four with three rounds left.
And it was Brigginshaw who came up with the big moments against a Raiders side coming off four straight wins.
After Canberra led 8-0 early through two tries, Brigginshaw swung the momentum of the match when she took it upon herself to run the ball in the halves.
The Brisbane veteran dummied and stepped her way through from 35 metres out, before sending Shenae Ciesiolka over to reduce the margin to two.
And after Brisbane took the lead through the fit-again Julia Robinson just before halftime, it was Brigginshaw who stood up after the break.
The 33-year-old got forced her way over from dummy-half in the 42nd minute for a 16-8 lead, an advantage they never surrendered.
The only concern for Brigginshaw and the hosts was a head clash with seven minutes to play.
The Jillaroos co-captain passed a head injury assessment but will now need to overcome her nose injury to face sixth-placed Cronulla next Saturday.
"We have our backs to the wall," Broncos coach Scott Prince said.
"We had two choices. Stand there or do something about it.
"We're going to get that all through the season. We have to win. We put ourselves in a position and we have to get ourselves out of it."
In Sunday's second game, Newcastle withstood a late surge from Cronulla to score a 22-14 win at McDonald Jones Stadium that dents the Sharks' finals hopes.
Cronulla were down 10-0 after nine minutes and 22-0 after 45 but finally began to capitalise on the Knights' errors in the second half and stormed back into the contest with three unanswered tries.
Forced onto the left wing after Andie Robinson left injured, prop Chloe Saunders was an unlikely try-scorer when she crashed over for the Sharks' third and a 22-14 scoreline.
But Tayla Preston couldn't make the sideline kick that would have made it a one-score game and the Knights held on to consolidate second spot.
Cronulla were left to wonder what could have been if Tiana Penitani had not been ruled to have obstructed Jesse Southwell in the lead-up to a potential try from Talei Holmes.
"I had no idea that Jesse Southwell was actually there. I was pushing up on the inside of my winger to potentially be an option so I disagreed with the call," Penitani said.
"But we've just got to get on with it.
"I was really proud of the girls, how we fought back."
The Sharks are now two wins off the top four with three rounds left, so must beat Brisbane next week to retain hope of a finals berth.
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