West Coast officially have a weakness and Port Adelaide have taken full advantage to post a 42-point win in their AFL clash at Optus Stadium.
In a game that featured periods of driving rain on Good Friday, Port booted nine goals to two in the opening half to set up the 13.17 (95) to 8.5 (53) triumph.
West Coast have proven to be the kings of dry-weather football, but slippery conditions are fast becoming an Achilles heel for the defending premiers.
In round one against Brisbane, West Coast copped a 44-point hammering in greasy conditions at the Gabba.
And against the Power in front of 49,290 fans, West Coast's big guns could barely fire a shot in the wet and windy conditions.
Key forwards Josh Kennedy, Jack Darling and Oscar Allen managed just one goal between them, with West Coast only avoiding an annihilation courtesy of a five-goal haul to speedster Jack Petruccelle.
In contrast, the slick Power had 10 different goalkickers in a dazzling team display.
The Power led by 49 points by halftime - an astonishing figure given the downpour in the first half.
Some Eagles fans left the stadium at that point, such was their dismay at how poor West Coast were playing.
The six-goals-to-one second term tore the game wide open, with West Coast's defence unable to cope with the constant Power raids in the driving rain.
With tall timber Kennedy, Darling, Allen, Tom Hickey and Nathan Vardy proving to be ineffective in the wet, Port Adelaide cashed in.
West Coast showed a bit more fight in the second half when the rain stopped, but the game was already over.
"We've got 15 or 16 night games this year, so if we can't play in slippery weather we're going to be in strife," Eagles coach Adam Simpson said.
"I hope it's a bit deeper than that. It's something we need to address, but I don't think it's the sole reason for our inability to compete tonight."
Power co-captain Ollie Wines was superb with 35 disposals, seven clearances and a goal, while Tom Rockliff, Sam Gray, and Sam Powell-Pepper were also influential.
Eagles skipper Shannon Hurn and Brad Sheppard fought valiantly in defence, while Petruccelle's pace helped him to boot his career-high five goals.
But West Coast boasted few other winners in a game where Port Adelaide won the inside-50m count 69-38.
"I think we were strong over the ball and took our opportunities," Power coach Ken Hinkley said of his team's powerful second quarter.
"We played reasonably smart football, because the conditions got difficult. We took our chances that quarter."
The result leaves both Port Adelaide and West Coast with 3-2 records.
Australian Associated Press