Second-half goals from Jorge Grant and Lawrence Shankland extended Hearts' unbeaten run to eight matches and drain Aberdeen's hopes of finishing third in the Scottish Premiership.
Grant took over penalty duties from top scorer Shankland, who had missed his last three, and stroked effortlessly into the top corner after Nicky Devlin was penalised for handball following an on-field review.
But despite losing his form from the spot, Shankland proved again what a potent finisher he is by guiding in Hearts' second from the edge of the box with the outside of his right boot.
That killed Aberdeen's chances of winning, and likely of finishing best of the rest again as they slip 19 points behind third-place Hearts, albeit with three games in hand.
When Grant confidently finished his penalty it felt harsh on Aberdeen, who created the better chances in the first half, and had the ball in the net too.
Bojan Miovksi curled a wonderful shot beyond goalkeeper Zander Clark, but referee Kevin Clancy was called to have a second look by the video assistant referee, and ruled the Aberdeen striker had tripped Beni Baningime on his way into the box.
It felt like a significant moment for the visitors, who have come under increasing scrutiny for their lowly league position, and their habit of fading in games returned as Hearts took control.
When the ball struck Devlin's outstretched arm to give Grant the chance to break the deadlock, Steven Naismith's side never looked back and Alan Forrest and Kenneth Vargas could have added to the scoreline.
And despite being fairly quiet, it was almost inevitable Shankland would have a say against his former club. After getting some luck with the bounce of the ball, the Scotland striker superbly placed in his 19th goal of the season and eighth in his last eight games.
More to follow.