Substitute Oday Dabbagh scored a late extra-time winner as Aberdeen eventually ground down nine-man Hearts to reach their first Scottish Cup final since 2017.
With the Hampden semi-final poised at 1-1 approaching half-time, Jambos defender Michael Steinwender was shown a straight red card for denying a goal-scoring opportunity by bringing down Topi Keskinen.
The 10 men held firm to take the tie into extra time and looked like forcing it all the way to penalties before Cammy Devlin was dismissed in the 116th minute. The Dons capitalised within two minutes of the Australian’s dismissal when Palestinian forward Dabbagh fired home from close range to secure a 2-1 victory.
Jimmy Thelin’s side will face the winner of Sunday’s semi-final between Celtic and St Johnstone back at the national stadium on May 25 as they bid to land the trophy for the first time since 1990.
Despite the spirit Hearts showed to hold out for so long with a numerical disadvantage, ultimately it was another damaging result in Neil Critchley’s quest to win over an increasingly sceptical fanbase on the back of his side’s failure to make the top six of the William Hill Premiership the previous weekend.
The Jambos head coach made three changes to the side that started the 0-0 draw at Motherwell, with Devlin, James Wilson and Lawrence Shankland all restored.
Aberdeen made just one change to the side that started the 2-2 draw at home to 10-man Rangers as goalkeeper Dimitar Mitov took over from Ross Doohan after recovering from a shoulder injury sustained on international duty with Bulgaria last month.
Hearts settled quicker than the Dons, who looked nervy in the opening 10 minutes, with Jamie McCart going close and Elton Kabangu having a couple of decent opportunities.
After a fraught opening for Aberdeen, they started to find their way into the game and made the breakthrough from their first real chance in the 18th minute.
Pape Gueye rose highest to head Leighton Clarkson’s corner off the underside of the bar and as the ball came down it struck the back of helpless Hearts keeper Craig Gordon and rolled over the line.
Hearts managed to regain their composure, however, and they drew level in the 28th minute when captain Shankland met James Penrice’s cross from the left, took a touch and rifled a clinical finish through the legs of Mitov from eight yards for his first goal since February and only his fifth of the season.
The Edinburgh side suffered a huge blow a minute before the break when Steinwender was shown a straight red after bringing down Keskinen as he burst away from him just outside the centre circle.
Critchley responded by sending centre-backs Craig Halkett and Frankie Kent on in place of attackers Wilson and Kabangu, switching from 4-4-2 to a more compact 3-5-1 formation.
Aberdeen threatened in the 53rd minute when Gueye glanced a header wide from Ante Palaversa’s cross but the 10 men in maroon generally kept their opponents at arm’s length as they stood firm to take the match into extra time.
Hearts’ task was made even more difficult in the 116th minute when Devlin was sent off for a second bookable offence after fouling Dante Polvara.
The Dons eventually got the winner in the 118th minute when Dabbagh forced in the rebound after fellow substitute Jack Milne’s shot was saved by Gordon.