Aberdeen maintained their 100% Scottish Premiership record thanks to a late goal from Ante Palaversa and poor finishing from 10-man Hearts at Pittodrie.
Palversa crashed in a rising shot on 88 minutes following a bustling run and cut-back from fellow substitute Duk, making his first appearance of the season.
Bottom-of-the-table Hearts had gone 2-1 up through a wonderful strike from Blair Spittal only for Nicky Devlin to find a smart volleyed equaliser and Jorge Grant to pick up a second yellow card.
The Dons had made the perfect start when a heavily deflected shot from Topi Keskinen looped in after just two minutes.
The visitors came roaring back though. Lawrence Shankland squandered two great opportunities to level before setting up the equaliser with a smart, cushioned pass for Frankie Kent to net from close range.
Grant and Kye Rowles threatened and Kenneth Vargas was guilty of a terrible miss, chipping over with just goalkeeper Dimitar Mitov to beat.
Spittal's fine goal from 25 yards had Hearts heading for their first domestic win of the season, but Aberdeen had other ideas, taking their incredible run to 13 successive victories under manager Jimmy Thelin.
Seven of those have come in the league, matching Celtic at the top of the table, with those two meeting in Glasgow when the contest resumes after the international break.