Wanneroo was heavy favourite to win the title, having progressed to the final with a 61-run demolishment of Balga.
Landsdale, on the other hand, did it tough against the fancied Ballajura, but defended 132 in rolling the City of Swan side for 108.
The final defied the favoured prediction when Landsdale, which bowled first, dismissed Wanneroo for a meagre 66 in the 17th over.
The underdogs did not waste the prime opportunity they had given themselves for victory, taking just 10 overs to pass the total for the loss of one wicket.
Association secretary Dave Fernandez summed up the result with a fitting sporting cliché.
“On the face of it, this would seem a mismatch – Wanneroo were considered the big dog on the park and Landsdale the smaller terrier,” he said.
“But as it so often goes, it’s not the size of the dog in the fight that matters, but rather the size of the fight in the dog and Landsdale certainly had some fight in them.”