Rockingham are the first team into the Peel Football League grand final after defeating Baldivis by 29-points.
The Brumbies battled hard without key names Blaine Johnson and Benjamin Higgs but were unable to overcome quick ball movement.
Tyler Sutton led the way for the Rams booting three goals in the 10.12.72 to 6.7.43 victory.
Pinjarra are out of the race after falling to the Mandurah Mustangs by just four-points.
Both sides were inaccurate in front of goals but the visitors were able to win the more shots on goal to triumph 9.15.69 to 9.11.65.
The Brumbies and Mustangs will meet in the preliminary final on Saturday afternoon at a venue to be determined on Monday night.