The Dons' dismal home form continued as they again failed to hit the goal trail.
They were made to suffer as Hearts substitute Gary Wales scored late on to make it another miserable night for the Dons faithful.
Alan Maybury made good progress down the right before driving in a low cross which David Preece did well to hold in the opening stages.
In the 18th minute Aberdeen should have gone ahead when Leon Mike picked out Paul Sheerin whose cross-cum-shot was missed by Steven Tosh when it seemed easier to score.
Minutes later Hearts passed up a good chance when Mark De Vries headed over Jean Louis Valois' cross when he had time and space to pick his spot from around eight yards out.
With half time approaching James McAllister's blushes were saved when he nearly put through his own goal but Preece saved the day.
Hearts continued to press and in the 54th minute Scott Severin passed up another good chance when he drove Valois' corner high over the bar.
The Dons ought to have gone ahead in the 60th minute when Sheerin's cross found Tosh but his header was too close to Tepi Moilanen.
Moilenen again showed his class as he dived full length to touch Chris Clark's fierce drive over for a corner.
McAllister was then short with a backpass which was intercepted by Wales. However with only Preece to beat he shot into the welcoming arms of the keeper.
Disaster struck for the home side as Hearts scored in the last minute. Valois' prod through the middle put Wales clear of the Dons defenders and the striker raced through on goal before slipping the ball under the advancing Preece.
The impressive Moilanen again came to his side's rescue as he got down low to smother Scott Michie's eight-yard effort at the expense of a corner.