At Hillcrest Oval, the one-day contest had the 2013-14 premiers manage just 81 runs off 36 overs in a six-wicket loss.
Roos opener Aaron Brunner was his side’s only batsman to reach double figures, scoring 25.
The hosts lost four batsmen and took only 28 overs to chase down the total, led by Mitchell Todd (26) and Robert Guy (21).
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READ NOWWanneroo’s Kyle Millar impressed with the ball taking 2-28 from his 10 overs.
The Roos face Joondalup in an early-season northern derby on Saturday.