The Blues are chasing their first flag in the competition on Sunday but standing in their way is a formidable South Warrnambool outfit, fresh from a week off.

The Roosters have reigned supreme in all three of their previous clashes in 2022 but Blue Ascha Peterson believes her side can match it with its rivals on the biggest stage.

"I think we've definitely improved. I'm quietly confident as (coach) Dean (Kilpatrick) said last week," she said.

"I think we've got it."

Peterson's teammate Emma Zerbe also thinks her team has a chance to lift the cup.

"I think it's going to be a tough game but I think we can maybe get there," she said.

Grand finals are renowned for being no ordinary game and Peterson expects an added layer of intensity on Sunday.

"South and Warrnambool have always had a bit of a competition between them," she said.

The Blues qualified for the grand final with a nail-biting three-point preliminary final upset over Horsham Demons on Sunday.

It was the Blues' accuracy and strong defence that ultimately got them home 1.2 (8) to 0.5 (5).

Lily Jenkins and Emily Mahony were the Blues' best players while co-captain LaToya Folima had the honour of kicking the sole goal of the match.

Zerbe was delighted with the result after the Blues entered as underdogs.

The Roosters, who finished minor premiers, earned their place with an 18-point win over the Demons the previous week.

Rosie Pickles and Lucy Jones were dominant for the Roosters and will no doubt be key players for their side on Sunday.

Peterson said her side's strengths were "attacking the ball" and tackling.

"I think last week when we played Horsham, we nearly made 300 tackles or something," she said.

"I think our back-line is very strong too."

The under 18 decider gets under way at 12.30pm at Reid Oval, followed by the women's grand final between Horsham Demons and Hamilton Kangaroos at 2pm.

The Demons will start favourites in that clash after claiming the minor premiership and only suffering one loss for the season - to Tyrendarra in round four.

The Kangaroos finished the regular season in second position and earned their spot in the decider after accounting for South Warrnambool in windy conditions 3.5 (23) to 2.2 14 on Sunday.

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