Aberdeen boss Jimmy Thelin was delighted to see Duk among the goals and Pape Habib Gueye back on the pitch as the Dons overcame 10-man Elgin to end a barren streak of 13 games without a win.
The Dons started Saturday’s Scottish Cup tie on the back foot, with Elgin’s Lewis Hyde coming close to an opener within the first 10 minutes.
However the Premiership side grew into the game and Shayden Morris netted from close range to calm their nerves.
Morris was played in by Duk for the opener, and the Cape Verde international added a second with a header that only just crossed the line, before curling home a third in injury time.
Elgin defender Lyall Booth was booked for protesting about the awarding of the second goal and saw red just three minutes later following a second booking for a foul on Duk.
Those were Duk’s first goals of a season which started with him on strike, and Thelin said: “The way Duk scored them was important, he was good in the build-up and arrived in the right spot.
“It’s always about the positioning and to be there, so it was good goals he scored today.
“Even after the first goal, Elgin stayed in the game. I was really impressed by them but at half-time we spoke about taking a big step, otherwise the game could be very tricky.
“Pape was really happy to play. We spoke about saving his energy but he gave everything from minute one, which was really nice to see.
“He’s a good player to have in the team, he has a presence inside the box and creates space for others.
“It was a while ago since we won a game but for me even in tough times we have to be stable and keep the direction.
“Even with a win today, we have a lot of things to keep working on and that’s the focus.”
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