The Pat Sherlock-coached side will play Horsham Demons in the decider after overcoming South Warrnambool in a wind-affected preliminary final at Tyrendarra Recreation Reserve on Sunday.

The Roos kicked the first three goals of the game and held on as the Roosters rallied late, winning 3.5 (23) to 2.2 (14).

"I was a bit nervous coming down - we had a few unavailable to play so I wasn't sure how the girls were going to respond but everyone played really well," Sherlock said.

"We started well in the first quarter so I thought we were going to control it, if we kept doing the things we needed to do. We came with the right attitude, we just had to execute the four quarters."

A chance to redeem themselves against Horsham - the team which beat it by a goal in the qualifying final - is spurring on the Kangaroos.

"We'll try and change a couple of things because if we do the same thing we might get the same result," Sherlock said.

Warrnambool advanced to the under 18 grand final with a gritty 1.2 (8) to 0.5 (5) win against Horsham Demons in wet, muddy conditions.

The Demons finished atop the ladder but bowed out in straight sets after losing to South Warrnambool in the qualifying final.

Blues coach Dean Kilpatrick said a grand final berth was reward for his hard-working group.

"We have 16 new girls this year and a few numbers so a few girls miss out (on playing) each week," he said.

"Lucy (El-Hage) and Latoya (Folima) have been at the club since the very start (of our women's program) so for those two girls it's very pleasing to hopefully finish off their (junior) careers with a fantastic game and potentially a premiership."

Kilpatrick has witnessed growth in his players' skills and confidence throughout the season and is excited about the prospect of playing against cross-town rival South Warrnambool - a powerhouse since the competition's berth - in a grand final.

"The girls are great. They come and have a good time and it's fun to be around," he said.

The league will conduct its awards night on Friday night.

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