On a day when the junior and some lower-grade matches were abandoned, the first-grade competition went ahead, but the wonders of Duckworth Lewis were to the fore.
This benefited Wanneroo first-grade, which bowled tightly and, in the main, fielded with efficiency to restrict the home side to 166.
Bayswater-Morley was in deep trouble at 6-113, but a spirited finish left Wanneroo with a challenge.
Jake Fawcett led the Wanneroo batting with a quick-fire 32, while youngster Alex Burton demonstrated growing maturity with an undefeated score of 19.
Rain caused the umpires to consult their calculators and Wanneroo had the better run rate and were awarded the victory.
The best of the bowling for Wanneroo was by team captain Chris Quelch with 2-28 and man-of-the-match Jake Fawcett with 2-32.
In second-grade, Jason Parry scored 43 and Jordan King 39 at Kingsway to set them on their way to a total of 9-145.
In reply, Bayswater-Morley lost eight wickets in scoring 137.
Jarrad McPhee with 3-27 and Josh Quelch 2-22 were the leading bowlers for Wanneroo.
Despite the efforts of Michael Ardagh, who took 2-23 in the third-grade contest, Bayswater Morley posted 8-194.
Wanneroo in reply went within an ace of victory with a total of 6-193.