Collingwood have executed one of the biggest boilovers in AFL finals history and are within one win of their 16th premiership.
The Magpies stunned reigning premiers Richmond in Friday night's preliminary final, blowing them away in the second quarter and holding on grimly in the last quarter for a 39-point triumph.
The 15.7 (97) to 8.10 (58) win ended the Tigers' record 22-game winning streak at the MCG.
It rivals Carlton's famous 1999 win over Essendon as the biggest preliminary final upset in VFL/AFL history.
Giant American Pie Mason Cox was awesome, taking 11 marks and kicking three goals; Jordan De Goey kicked four goals while midfielder Steele Sidebottom was best afield to continue his outstanding finals series.
Tigers key forward Jack Riewoldt was a lone hand with five goals.
Collingwood will join Essendon and Carlton with the most premierships if they win Saturday week's grand final, which looked unthinkable 12 months ago when coach Nathan Buckley survived massive pressure to keep his job.
Collingwood finished 13th last season, just as the Tigers climbed from the same ladder position in 2016 to break their premiership drought.
This is Collingwood's first finals series since 2013 and their first grand final since losing to Geelong in 2011, while their last premiership was celebrated in 2010.
The Magpies opponent will be the winner of Saturday's West Coast-Melbourne preliminary final in Perth.
Richmond kicked the first two goals of the last term, reducing the margin to a gettable 21 points, but another big mark from Cox on the wing led to Adam Treloar's goal at 10 minutes and that ended any hope of a Tigers comeback.
Collingwood were on from the start, taking a 23-point lead at quarter time.
The reigning premiers looked rattled, with Richmond defenders repeatedly making basic errors, but no-one could have predicted what happened next.
Cox lit up the MCG, converting three strong marks into three massive goals in the opening 11 minutes of the second term.
He blew the margin out to 42 points and it is surely the first time at any Australian sporting event where local supporters have chanted "USA, USA".
The Magpies kicked another three goals to add emphasis to the rout, extending their lead to a game-high 53 points.
Tigers star Dustin Martin, who was on light duties at training this week because of a corked thigh, clearly was not at full fitness and spent much of the first half playing deep in attack.
Inevitably, Richmond counter-attacked and they had the last four scores of the second term.
Jack Higgins kicked their second goal just before the main break and that made the half-time margin 44 points.
That left any Magpies fans who knew their history with some nerves.
It was the same advantage that Collingwood had over Carlton at half-time in the famous 1970 grand final, which the Blues stormed back to win.
Richmond kicked four goals to two in the third term and reduced the margin to 33 points at the last change, but they were coming from too far back.