Canberra coach Darrin Borthwick blamed a contentious no-try ruling for changing the course of the Raiders' 20-10 defeat by Sydney.
With the Roosters leading 10-4 early in the second half at Allianz Stadium, forward Lili Boyle forced her way over the line.
Referee Kasey Badger ruled Roosters winger Brydie Parker's boot was beneath the ball, and the bunker upheld her decision after reviewing replays.
Borthwick said the Raiders could have levelled at 10-10.
"Absolutely it was (the turning point). It's hard to say where that game would have went if we had got that one," he said.
"It's a try every day of the week. the game is going crazy to be honest."
Roosters coach John Strange initially thought Boyle had scored, but said the replay showed Parker's pink boots underneath the ball.
"Brydie's pink boots got under there in the end," Strange said.
Strange also criticised Sheridan Gallagher's hair-pull on Isabelle Kelly, saying it stopped a likely try and warranted a sin-bin, but not a penalty try.
The Roosters scored four tries to two, though Hollie-Mae Dodd's late try left Canberra within a converted try in the final eight minutes.
Tarryn Aiken's angled 67th-minute try sealed the win and sent Sydney to its third straight NRLW grand final. Aiken missed last year's final with an ACL tear.
The October 4 decider offers the Roosters a chance to add to their 2021 and 2024 premierships after losing the 2025 final to the Broncos.