The Warriors have become the first team to beat Brisbane in NRLW history with a 10-8 win at the Sydney Cricket Ground on Saturday.
The Warriors will qualify for the grand final if the Sydney Roosters beat St George Illawarra in Sunday's stand-alone match at Leichhardt Oval.
Meanwhile, the narrow loss also guaranteed defending champions Brisbane a second straight decider, while the Roosters are officially out of contention.
After a tragic week that included centre Honey Hireme lose her mother and coach Luisa Avaiki her father, the Warriors led 10-0 and then held on from there.
"It's been a tough week," stand-in Warriors coach Justin Morgan said.
"Obviously Louisa had some bad news as did Honey. It's a pretty tight-knit group of players and club.
"When news like that hits, you're often not sure how people are going to react.
"I think you saw out there that the girls responded for Louisa. And against a side like the Broncos who haven't been beaten in this competition."
Neither Hireme or Avaiki were at the ground for the match, with both a chance to be there next week despite Hireme having missed the regular season to be with her mother.
On the field, front-rower Annetta Nuuausala was the star for the Warriors as she scored a crucial try before half time and finished with a game-high 101 metres and five tackle busts.
After Georgia Hale and Atawhai Tupaea put Madison Bartlett over to open the scoring early, Nuuausala worked her magic.
The steam-rolling prop carried four Broncos across the line to score, as the sister of former NRL player Frank Paul was easily the most powerful on the field.
The win could have come at a cost but, with halfback Charntay Poko suffering a rib injury which could put her in doubt for next week if they qualify.
Meanwhile centre Amy Turner was the Broncos' best.
She helped Tamika Upton cross on the wing just after the break to put them back in the match, and scored herself with 17 minutes to play.
However, when Chelsea Baker's conversion attempt hit the post, it allowed the Warriors to hold tight and keep their season alive.
"A loss for the Broncos had to come at some point. I would certainly rather it be this week than next week," coach Kelvin Wright said.
"They are really disappointed even knowing they are going to the grand final. I certainly don't think there will be any complacency."
AAP