Duk was the toast of a packed-out Pittodrie as he returned from exile to help Aberdeen eke out a 3-2 victory over 10-man Hearts and maintain their perfect start to the campaign under Jimmy Thelin.
The Dons extended their remarkable winning run to 13 matches in all competitions but only after being given a huge scare by bottom-of-the-table Hearts, who were on top for long periods until Jorge Grant was sent off in the 75th minute with the match poised at 2-2.
Duk was given a huge ovation from the home support as he came on for his first appearance of the season on the hour mark after being temporarily suspended by the club for going AWOL in the summer.
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The striker was the man fouled by Grant as he picked up his second yellow before he laid on an 88th-minute winner for fellow sub Ante Palaversa, sparking delirious scenes among a home support who spent the closing stages singing about their team "going to win the league", and "bring on the Celtic", a reference to their next opponents after the international break in what promises to be a mouth-watering top-of-the-table showdown.
Thelin sent out the same team that started the 2-1 win at Dundee the previous week, while interim Hearts boss Liam Fox made six changes to the side that started the Conference League win over Dinamo Minsk in Azerbaijan on Thursday.
Aberdeen got off to the perfect start in the second minute when Topi Keskinen's shot from the edge of the box took a significant deflection off Kye Rowles and eluded Craig Gordon on its way into the net after Stephen Kingsley had been caught in possession.
The visitors responded strongly and Lawrence Shankland spurned two big chances to equalise before Jamie McGrath made a vital intervention to stop Grant knocking in Daniel Oyegoke's cross.
Rowles had to get back to make a vital block on Dons striker Kevin Nisbet but Hearts continued to be the more threatening side, with a couple of teasing, inswinging Yan Dhanda crosses from the left just eluding Grant and then Frankie Kent.
A high, looping effort by Dhanda from 25 yards out was tipped over by Dimitar Mitov in the 35th minute, resulting in a corner from which Hearts equalised. James Penrice's delivery found its way to Shankland, who cleverly dinked the ball back across goal for Kent to nod home.
Shankland - who had been booked on the half-hour - was fortunate to avoid a second yellow after a couple of fouls just before the break.
The visitors spurned a glorious chance to go ahead in the 53rd minute when Kenneth Vargas darted clear on goal after capitalising on hesitancy between Jack MacKenzie and Gavin Molloy, but - with the option of squaring to Shankland - the Costa Rican opted to try and chip Mitov, and the ball drifted over the bar.
Duk entered the fray to rapturous applause on the hour but Hearts remained the side in the ascendancy and they took the lead in the 63rd minute when Blair Spittal rifled in a low shot from the edge of the box.
The visitors' advantage lasted just two minutes, however, as Nicky Devlin - preparing to join up with the Scotland squad this week after earning his first call-up - shot home from 20 yards out. Grant was booked for dissent in the aftermath of the goal and he was then shown his second yellow for chopping down Duk.
The Dons suddenly had the upper hand and after a sustained spell of pressure Palaversa lashed a shot high into the net from a Duk cutback.
What the managers said...
Aberdeen manager Jimmy Thelin:
"Things didn't go exactly how we planned, but that's football sometimes. We did some mistakes today but I don't think it's the right day to analyse that. We have to think about the atmosphere, the substitutes we made and how they made an impact in the game.
"The whole of Pittodrie was bouncing and these good feelings and the character of the team when it's not going exactly as we planned - this hunger to try to find the winning goal, even if they were down to 10 men - I'm so happy with that today.
"You can see the fire in the eyes of the players and how they push each other and really compete, together with the fans at Pittodrie.
"I think everybody could feel the atmosphere today was something extra, and it was amazing, actually."
Hearts interim manager Liam Fox:
"I feel disappointed, I feel frustrated. I thought we were good for at least a point.
"The red card definitely changes the flow of the game. The other thing that's worth mentioning is that their second goal, the ball's actually still moving from a free-kick. They go up the park and score.
"Jorge Grant is then booked for dissent because he's complaining about the ball moving and then he gets sent off for a challenge. It's a sore one to take."