In the last game of Round 23, West Coast sneaked into the finals after pulling-off a 29-point victory over Adelaide.
The 15.10 (100) to 10.11 (71) triumph was just enough for the Eagles to leapfrog Melbourne into eighth spot by only 0.5 per cent.
The Eagles will travel to face Port Adelaide in an elimination final after a fitting farewell to Domain Stadium and a crazy 2017 home-and-away campaign on Sunday.
Adam Simpson's men knew what they needed to do before the opening bounce but even though minor premiers Adelaide were already guaranteed to finish on top of the ladder, the Eagles had to fight until the desperate last moments to book a top eight spot.
West Coast hit the ground running, opening up an 18-point lead by quarter-time and giving themselves hope.
At half-time the Eagles were only two points shy of the margin they needed to nudge Melbourne out of the finals.
By the final change, the Eagles had extended their break to 31 points but were just hanging on.
Their history of fadeouts this season was the elephant in the room and the result was on a knife's edge when WA product Mitch McGovern booted the opening goal from deep in the pocket for the Crows.
When Paul Seedsman split the middle on the run at the 15-minute mark the Eagles were only clinging onto eight spot by 0.1 percentage points.
With five minutes to play, everything turned as Charlie Cameron drove a dagger into West Coast's finals hopes, moments after Josh Kennedy missed from the goalsquare as he was tackled by Kyle Hartigan.
At that stage, Melbourne was back in the top eight.
But then much-maligned duo Lewis Jetta and Jack Darling produced two final unforgettable moments to go into the annals of West Coast's history at Subiaco Oval.
First, Jetta dodged two tacklers and converted a sublime checkside goal, then Darling ran back with the flight and collided with the goalpost as he marked and extended the margin to 29 points.
As the final siren sounded, the raucous crowd of 39.367 supporters leapt to their feet as one to celebrate a third-straight finals appearance.
"We left it to the last four minutes of the season to qualify, I'm not sure if that's happened before – it probably has – but we've been in those positions a lot this year coming into the last quarter and being in a good position to win," Simpson said post-match.
"To do that today in such an important game, and it was a pretty emotional week as well with players retiring left, right and centre and the last game at Subi, East Perth were fighting for a finals spot as well.
"I'm pretty proud of the players and their resilience throughout the week to stay pretty focused on the process."
West Coast's victory was inspired by retiring champion Sam Mitchell (34 disposals) and will extend his career and that of fellow Brownlow medallist Matt Priddis for at least one more match.
Former North Melbourne tall Drew Petrie will also retire at the end of the campaign, coach Adam Simpson announced post-match.
The Eagles owed plenty on Sunday to Andrew Gaff (32 disposals, one goal) and sidekick Luke Shuey (28 and a goal) whose work helped overcome a mammoth 33-49 clearance deficit.
West Coast also found some unlikely avenues to goal after spearhead Josh Kennedy was held to just one goal by Kyle Hartigan, who filled in admirably for injured full-back Daniel Talia.
Kennedy's solitary major means he fell four goals short of a third-straight Coleman Medal, which was instead won by Sydney superstar Lance Franklin with 69 majors.
While the Crows, who were without captain Taylor Walker, have finished on top of the ladder, Don Pyke could have some concerns after ending with two losses before facing Greater Western Sydney at home in a qualifying final.
However, there were positives to take from the match.
Brothers Matt and Brad Crouch were unstoppable with 45 and 42 possessions respectively on Sunday and will provide Rory Sloane (38) with much-needed support during September.
In the process, the Crouch brothers broke the all-time disposal record for siblings in a season, previously held by Chad and Kane Cornes.
The Crows racked up 415 disposals and Pyke admitted his side was guilty of not attacking directly enough at times.
"Credit to West Coast, they came here with a lot to play for and they found a way to get it done," he said.
"We didn't start particularly well from a scoreboard viewpoint but we were creating some opportunities.
"I thought we didn't use the ball as good as we have and (we were) probably guilty a bit of overuse at times."
MEDICAL ROOM
West Coast: Jeremy McGovern had a sore left shoulder that forced him from the ground in the second term but he returned and played out the game.
Adelaide: Luke Brown battled a migraine through the game and Alex Keath will be monitored after suffering concussion from a heavy hit.
WEST COAST 4.1 8.4 13.5 15.10 (100)
ADELAIDE 1.1 5.5 7.10 10.11 (71)
GOALS
West Coast: Cripps 3, Hutchings 2, LeCras 2, Vardy, Redden, Gaff, Shuey, Kennedy, Petrie, Jetta, Darling
Adelaide: Betts 2, McGovern 2, Milera, Smith, Jenkins, M Crouch, Seedsman, Cameron
BEST
West Coast: Mitchell, Gaff, Hurn, Shuey, Priddis, Cripps
Adelaide: M.Crouch, B.Crouch, Sloane, Laird, Jacobs, Hartigan
INJURIES
West Coast: Nil
Adelaide: Nil
Reports: Nil
Umpires: D.Margetts, N.Williamson, S.Ryan
Official crowd: 39,367
