Collingwood has come from 18 points down with two fit men on the bench at three quarter time to upset West Coast in its bravest victory under Magpies coach Nathan Buckley.
Jordan De Goey was the match winner with four second half goals and a game-changing tackle that allowed Jamie Elliott to kick the goal that gave the Magpies the lead with just two minutes to go.
Collingwood kicked the final five goals of the game to win the dramatic contest 13.15 (93) to 13.7 (85) and tipped the Eagles out of the eight.
It also kept its slim finals hopes alive and shows the team has rediscovered the purpose it seemed to lose a fortnight ago.
On the other hand, West Coast were disappointing losing its fifth game away from home for the season and looking anything but a finals contender.
It appeared to have the game in its keeping with just 10 minutes remaining when Elliot Yeo ran into an open goal but he missed and the door was left ajar.
The Magpies worked through that door despite Darcy Moore being in hospital after injuring his neck three minutes into the second quarter and then losing Travis Varcoe to concussion just 10 minutes into the third quarter.
VIDEO: Darcy Moore's day ends early. Watch the second-quarter incident.
When Varcoe left the ground during the third quarter Collingwood was 15 points down and Josh Kennedy was dominating in his 200th game.
Kennedy had six goals on the board and looked to be leading a lack lustre Eagles to victory.
But Collingwood came alive sparked by De Goey who kicked two consecutive goals and lifted the Magpies, who were led brilliantly by Steele Sidebottom who was standing in as skipper for the injured Scott Pendlebury.
Levi Greenwood restricted Andrew Gaff to just 16 disposals, half his usual output and the Magpies dominated the inside 50s 56-45 and the clearances 37-29.
The 29-year-old Kennedy was too good for Tyson Goldsack in his milestone match taking six marks inside 50 and kicking six of the Eagles' first nine goals in just his second game back from injury.
Lynden Dunn, who had never won against the Eagles in nine previous attempts, moved on to Kennedy and quelled him.
When Moore went off the Magpies went with a small forwardline and the Eagles struggled with the Magpies quick low kicks into attack as their intercept markers, Jeremy McGovern, Shannon Hurn and Tom Barrass were unable to control the game from the back half.
After taking 10 intercept marks in the first half, the Eagles only managed two in the second half and the game changed.
Collingwood: Darcy Moore was taken to hospital for precautionary scans with a suspected neck injury. Travis Varcoe was concussed in the third quarter and did not reappear on the bench.
West Coast: Jeremy McGovern copped a knock to knee in the first quarter but he recovered well and played out the game. Luke Shuey was kicked in the knee and left the ground in the last quarter but he did not look to have suffered a serious injury.
Collingwood will attempt to upset ladder leaders Adelaide at the MCG on Sunday as it looks to shape the finals. West Coast heads home with big question marks hovering over them and chasing a percentage boosting win over the Brisbane Lions at Domain Stadium.
COLLINGWOOD 3.4 5.6 8.11 13.15 (93)
WEST COAST 4.2 7.3 12.5 13.7 (85)
Collingwood: De Goey 4, Elliott 3, Reid 2, Fasolo, Greenwood, Hoskin-Elliott, Adams
West Coast: Kennedy 6, Cripps 2, Darling 2, Yeo, Shuey, Vardy
Collingwood: De Goey, Treloar, Howe, Crisp, Grundy, Adams
West Coast: Kennedy, Sheed, Hurn, Yeo, McGovern, Shuey
Collingwood: Moore (neck), Varcoe (concussion)
West Coast: Nil
Umpires: Stevic, Deboy, Harris
Official crowd: 22,927 at Etihad Stadium