Led by the bowling prowess of player of the match Dylan Banks (5-27 and 7-59), Wanneroo claimed an outright victory at Burrendah Reserve on Sunday.
The Roos scored 151 in the first innings in reply to the Demons’ 81.
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Perth improved in its second dig to amass 150, but could not prevent Wanneroo taking a dominant win, with the visitors scoring the 80 runs required inside 26 overs.
Wanneroo’s Damon Parker (37 and 50) and Connor Smith (40) were best with the bat.
In the second-grade final, Joondalup lost to Willetton at Tompkins Park.
The Centurions were defeated in the first innings after scoring 115 in response to the Dragons’ 150.