Two rounds ago, the Roos were ninth and only out of the top six on quotient.
But back-to-back losses has had them fall to 11th, 15 points outside finals contention.
On Saturday at Lilac Hill, Wanneroo was looking to eclipse a formidable 362 but the Roos were all out for 262 in the 79th over.
Consistent performer Jake Fawcett was the Roos’ best with a patient 78 off 134 balls.The hosts’ Ashley Mucciarone impressed with 5-38.
Wanneroo faces University at Kingsway on Saturday.