The Eagles got the jump on the Crows with the first five goals, and the margin was never fewer than four goals from that point on as the hosts made it two-from-two this season against Neil Craig's men with a 26.9 (165) to 12.11 (83) win.
The Crows came to Perth in white-hot form having won 13 of their past 14 matches - the only blemish in that period a shock three-point loss to Richmond in round eight - and would have gone three games clear on top of the ladder had they beaten West Coast.
But the loss leaves them just one game clear of the second-placed Eagles, although Adelaide enjoys a far superior percentage and would still be favourite to finish No.1 at the completion of round 22.
The Crows' miserly defence, which had conceded an average of just 64.5 points after 16 rounds, was under siege from the opening bounce and simply could not cope with the Eagles' continual forward thrusts and fast centre breaks.
Daniel Kerr was simply outstanding throughout the afternoon and was at his in-and-under best at the stoppages. The 23-year-old finished with 34 disposals and two goals, while Ben Cousins (38 touches, two goals), Michael Braun (41 disposals) and Sam Butler (29) provided excellent support.
Quinten Lynch (four goals) and Ashley Hansen (three) provided excellent targets up forward, but it was the spread of 13 goal-kickers which won the Eagles the match.
Not only did West Coast's attack and midfield prove unstoppable, but its back-six was simply impenetrable at times, led brilliantly by Darren Glass, Jaymie Graham, David Wirrpanda and Daniel Chick.
Adelaide was without star defender Andrew McLeod, who underwent surgery during the week to correct a foot complaint, and the Crows desperately missed his run and rebound out of defence.
In his absence, Scott Thompson stepped up for the Crows with 30 touches and a goal, while Brett Burton (15 possessions and three goals), Tyson Edwards and Scott Stevens can also hold their head up high.
The Eagles suffered a setback before the match when vice-captain Andrew Embley was forced to withdraw with a hamstring injury; a blow compounded by the fact the team was already missing key personnel in Adam Hunter (knee), Dean Cox (collarbone), Mark Nicoski (ankle) and Chad Fletcher (hamstring).
But it certainly didn't affect the team's mentality, as the Eagles kicked the first five goals of the match to open up a 31-point lead after just 15 minutes.
Cousins started the onslaught with a successful snap after a great tap from Mark Seaby, and when Judd threaded one through from 42m out tucked away on the boundary line, the Eagles had kicked three goals in six minutes and Adelaide promptly sent numbers back to defence in an attempt to reduce the damage.
However, it did little to stop the home side as it slammed through another two goals, before Mark Ricciuto finally stopped the rot with a major at the 17-minute mark - Adelaide's first and only score of the term.
Brent Staker became West Coast's seventh individual goalkicker at the 21-minute mark when he kicked truly after taking a strong contested mark, giving the home side a well-deserved 33-point lead at quarter-time.
The highlight of the term was a fantastic aerial mark to Brett Burton, who launched himself above Adam Selwood before snaring the ball and crashing to the turf.
Lynch continued the domination with a goal just 51 seconds into the second term, but from there the Crows settled and started applying their well-renowned forward pressure, resulting in a goal to Tyson Edwards after Daniel Chick dropped a mark from the kick-in.
The Eagles responded with three of the next four goals - including a freak major from Steven Armstrong who somehow managed to get his left foot to the ball whilst being tackled on the ground - to extend the lead to 41 points nearing half-time.
But once again Adelaide capitalised on a mistake from the Eagles defence - this time an errant kick from Brett Jones - which was intercepted by Thompson, who banged through the six-pointer to reduce the deficit to 34 points at the long break.
The stats reflected the difference between the two sides at half-time. West Coast dominated possession with 201 disposals compared to Adelaide's 143, and also went inside 50 eight more times (24-16).
The result was put beyond doubt in a one-sided third term, as the home side piled on nine-goals-to-four to take a commanding 66-point lead into the final change.
Kerr was an inspiration in the quarter collecting 12 possessions and booting two goals, whilst setting-up countless others.
The final quarter represented party-time for the Eagles, who added seven-goals-to-four to run away with the fantastic win which could prove the catalyst for a successful finish to the season.
It was Adelaide's biggest loss since round 17, 2004, when a rampant Brisbane outfit ran amuck at the Gabba and recorded a 141-point win.
Adelaide coach Neil Craig acknowledged his side was well beaten by a well-drilled West Coast.
"The size of the margin certainly was extremely disappointing for us," he said. "We obviously knew we had a real game on our hands but we were just comprehensively beaten in just about every facet really."
"We've been in games like that before where the opposition have sort of kicked a couple of early goals, but, you know, we hope we can keep coming but in the end, the whole day, (West Coast) were just relentless in the way they played."
West Coast coach John Worsfold praised his players after the match, and attributed the win to "hard work and belief from everyone involved".
"We went out confident with our group that we could play some good football today and take it up to Adelaide," Worsfold said.
"To say that you'd think you could win like that - no you don't expect that, but that's always possible and any game can end up that way. I thought the way the defence worked and ran the ball that was great."
"Our midfield worked very well together both off our wings and through the middle and the forward line worked extremely hard and put on great pressure. It was certainly part of the package."
WEST COAST: 6.3, 10.4, 19.6, 26.9 (165)
ADELAIDE: 1.0, 4.6, 8.6, 12.11 (83)
GOALS – West Coast: Lynch 4, Judd, Armstrong, Hansen 3, Sampi, Kerr, Cousins, Staker 2, Butler, Braun, Seaby, Morton, Stenglein
Adelaide: Burton 3, Ricciuto 2, Goodwin, Edwards, Thompson, Hentschel, McGregor, Mattner, Reilly
BEST – West Coast: Kerr, Cousins, Braun, Glass, Chick, Butler, Hansen, Lynch
Adelaide: Thompson, Edwards, Burton, Stevens
INJURIES – West Coast: Nil
Adelaide: Nil
CHANGES – West Coast: Embley replaced in selected side by Morton.
Adelaide: Nil
REPORTS - Nil
UMPIRES - Kennedy, Chamberlain, Wenn
CROWD - 40,380 at Subiaco Oval, Perth
