Uche Ikpeazu left the Dons in a daze before staggering off the pitch with a concussion.
Hearts leapfrogged Hibs to go fifth in the Premiership as Aberdeen 's hopes of finishing second took a serious dent.
The Dons had the better of the first half in a bruising affair and Connor McLennan nodded them in front from close range after 16 minutes.
The Jambos looked off the pace in that opening period, but were transformed in the second half when a darting run from Jake Mulraney won a penalty, which was converted by Sean Clare after an hour.
Ikpeazu had fought a boisterous battle all afternoon with Dons defenders Andrew Considine and Scott McKenna and got the better of them both to slot home the game’s decisive goal 14 minutes from time.
It was a sweet moment for the burly frontman, who had missed an open goal early in the second half and was also controversially booked for diving in an attempt to win a penalty.
He celebrated his winner wildly, but his joy was short lived when he stumbled off the pitch with rubber legs after a head knock with Dominic Ball just 60 seconds after he netted.
He had recovered well enough to wave to the crowd as he was taken around the side of the pitch on a stretcher and Hearts held on to end Aberdeen’s recent impressive run of away form.
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Whistler John Beaton needed eyes on the back of his head on occasions and booked four players - Ball, Lewis Ferguson, John Souttar and Arnaud Djoum - in one melee near the end that saw Craig Levin on the pitch, along with both assistant refs.
The Hearts boss made his way onto the playing surface again after five nervy minutes of injury time, but this time it was to take the acclaim of his supporters in an impressive crowd of 17,800.
3 talking points
Heavyweight battle
This was a real battle of the heavyweights, with the respective roles of frontmen Uche Ikpeazu and Sam Cosgrove crucial to the gameplan of both sides.
It wasn’t especially pretty at times and was even industrial on occasions. It was a raw meat affair, riveting in parts, but leaves you wondering how well it will translate in Europe next season if they both make it there.
Passive Dons
Aberdeen were the better side first half, but strangely passive after the break when Hearts held sway and created the game’s best chances of note as Ikpeazu came to the fore. It wasn’t just the spring sunshine that forced Derek McInnes to discard his overcoat as he rolled up his shirt sleeves to try and spark his team from the sidelines.
Not a day for creativity
There are flair players in both squads, but sadly this was not an occasion in which the cream rose to the top. The desire of both sides to go long down the guts of the pitch reduced the impact of players such as McGinn, Stewart, Wighton and Brandon to bit part operators.
Hats off to Jake Mulraney for the game’s one bit of skill, a driving run into the Dons’ defence that led to the Jambos’ equaliser before Ikpeazu did brilliantly to find the winner.
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