The Rams struggled to contain Robert Young, who booted six goals for the Brumbies, helping his side to a nine-point victory.
Daniel Kimberley was also influential for the visitors with four goals, while Aaron Cleaver and Peter McGennisken were among Rockingham’s best.
Meanwhile defending Peel Football League premiers South Mandurah were no match for runners-up Waroona in a rematch of last year’s grand final.
It looked like business as usual for the Falcons, heading into the first change with an eight-point lead before the game tightened up in the second and third terms.
But it was a last-quarter blitz from the Demons that sealed the 57-point win, piling on 10 goals to two to win 18.8 (116) to 9.5 (59).
Steven Cameron booted four goals while Adam Clancy and Ben Wright grabbed three each.
Mitchell Dawson and Alfred Angi dominated the contest with Lance Lucas. Jayden Caratti and Gregory Nelson were also among the best for Waroona.
The Mustangs were unable to challenge Pinjarra, going down by 42 points at Rushton Park 15.17 (107) to 10.5 (65).
Pinjarra burst out of the blocks and never looked back, extending its lead at every change before a final-quarter hurrah from the Mustangs contained the damage.
Riese Wilkey booted four for the Tigers while Jeffrey Carter (3) and Joel O’Driscoll (2) were the only other multiple goal kickers.
Halls Head were also big winners, accelerating away from Mundijong Centrals to win by 50 points at Merlin Street Reserve after a tight first term.
Centrals would have gone in at quarter-time happy with its first term, which saw it just one point off last year’s second place team.
But Halls Head was able to edge away before a big last quarter helped it to a percentage-boosting win, 15.17 (107) to 8.9 (57).