Match ends, Hibernian 2, Aberdeen 3.
Aberdeen reached the Scottish Cup final for the first time in 17 years with victory over holders Hibernian.
Adam Rooney pounced on a defensive mix-up to put the Dons ahead 12 seconds after kick-off, and Ryan Christie's free-kick doubled their lead.
Substitute Grant Holt headed Hibs back into the game before half-time and the striker set up Dylan McGeouch to level.
But Jonny Hayes' shot deflected off Darren McGregor and beat Ofir Marciano for Aberdeen's winner.
Manager Derek McInnes, who won the League Cup with the Dons in 2014, now has a cup final against either Celtic or Rangers on 27 May to prepare for, with the Glasgow sides meeting on Sunday.
- McInnes lauds Dons effort to make final
- 'Pathetic' start cost Hibs - Lennon
- Player ratings by Craig Paterson and Russell Anderson
Aberdeen, who are second in the Premiership, will attempt to end a 27-year wait to win the Scottish Cup.
Their opening to the match was as perfect as it was calamitous for Hibs.
A McGregor mistake allowed in Rooney, who wasted no time in storming into the penalty area to slot home. The Aberdeen fans could barely believe it. It was a moment to make everyone of a Hibs persuasion sick to the stomach.
Aberdeen looked much the more assured side in the early stages. Hibs, in contrast, looked ill at ease as they struggled to find any sort of foothold.
Hibs looked groggier still as they went 2-0 down. Christie lined up a free-kick wide on the right on the edge of the box and the Hibs defence prepared for a cross.
Instead the on-loan Celtic player went straight for goal, whipping the ball in at pace and beating Marciano at his near post. It was a superb strike from Christie - selected ahead of Niall McGinn - but it was a goal the Hibs goalkeeper and defensive wall simply should not have conceded.
Having seen his side fail to get any traction, Hibs manager Neil Lennon realised something had to change tactically. A visibly disappointed Fraser Fyvie was brought off, replaced by the burly presence of striker Holt as Hibs changed tack.
It paid immediate dividends. Martin Boyle went on a great run and his cross to the back post was perfect for Holt to steer a header home with his first touch and give Hibs a vital lifeline.
The 36-year-old's introduction completely changed the dynamic. Suddenly the cup holders were winning the ball in the air and disrupting Aberdeen's flow as the match became a much more even affair.
Hibs drew level with a moment of real quality, with Holt again involved. McGeouch swept forward and played the ball to the feet of Holt, who flicked it back to the midfielder and McGeouch kept his composure to fire low past Joe Lewis.
It was a huge blow for Aberdeen who had earlier gone close through Shay Logan and switched to a back three, with Anthony O'Connor replacing Christie.
Suddenly the game of chess became more complex, McInnes now the manager with the dilemma and Lennon in charge of the side with the wind in their sails.
McGinn came on in place of Mark Reynolds, the Dons shuffling the pack again as the match moved towards its final quarter.
In the end, a stroke of luck gave Aberdeen the edge. Hayes did well to make space for a shot from long range, and the ball appeared to pose no real threat to Marciano's goal until it took a deflection off the unfortunate McGregor and trundled into the net.
Hibs had one last roll of the dice as they tried to hold on to the cup. Keeper Marciano came up for a stoppage-time corner and headed towards goal, but his counterpart Lewis held on to ensure Aberdeen progressed to the final.
- 25AmbroseSubstituted forGrahamat 88'minutes
- 8FyvieBooked at 24minsSubstituted forHoltat 34'minutesBooked at 78mins
- 10McGeouchSubstituted forShinnieat 63'minutes
- 6ReynoldsSubstituted forMcGinnat 69'minutes
- 3ShinnieBooked at 82mins
- 8ChristieSubstituted forO'Connorat 59'minutes
- John Beaton
- Shots on Target
Second Half ends, Hibernian 2, Aberdeen 3.
Attempt saved. Ofir Marciano (Hibernian) header from the centre of the box is saved in the top centre of the goal.
Corner, Hibernian. Conceded by Shaleum Logan.
Foul by Grant Holt (Hibernian).
Anthony O'Connor (Aberdeen) wins a free kick in the attacking half.
John McGinn (Hibernian) wins a free kick in the defensive half.
Foul by Ryan Jack (Aberdeen).
Substitution, Hibernian. Brian Graham replaces Efe Ambrose.
Own Goal by Darren McGregor, Hibernian. Hibernian 2, Aberdeen 3.
Graeme Shinnie (Aberdeen) is shown the yellow card for a bad foul.
Grant Holt (Hibernian) wins a free kick in the defensive half.
Foul by Graeme Shinnie (Aberdeen).
Attempt missed. Kenny McLean (Aberdeen) left footed shot from outside the box is just a bit too high from a direct free kick.
Foul by Marvin Bartley (Hibernian).
Kenny McLean (Aberdeen) wins a free kick in the defensive half.
Grant Holt (Hibernian) is shown the yellow card for a bad foul.
Foul by Grant Holt (Hibernian).
Jonny Hayes (Aberdeen) wins a free kick in the defensive half.
Corner, Hibernian. Conceded by Ryan Jack.