Aberdeen needed just 45 minutes to effectively book their place in the semi-finals of the Premier Sports Cup as they secured a comfortable 4-1 victory against Partick Thistle.
The Dons cruised into a three-goal lead with the minimum of fuss against their Championship opponents in a one-sided first half.
But the loss of an early goal from a set-piece after the break ensured the Dons were made to work hard for their semi date at Hampden.
Duk was rewarded for his man-of-the-match display against Hearts on Sunday by keeping his place in the starting line-up as Dons boss Jim Goodwin made three changes for the cup-tie.
Connor Barron, Jack MacKenzie and Jayden Richardson dropped to the bench as Matty Kennedy, Vicente Besuijen and Hayden Coulson came into the starting 11.
First half dominance yields three goals for Aberdeen
The Dons boss went with the ‘if it’s not broken don’t fix it’ approach as he kept faith with the three-man defence which earned a rare clean sheet in the 2-0 win against the Jambos.
But the tweak in personnel should have paid off in the third minute as Besuijen skipped past former Cove Rangers left back Harry Milne before crossing for Leighton Clarkson but he could not get enough power on his header and Aaron Muirhead was able to clear the effort for a corner.
The Jags responded with a long range effort from Cole McKinnon which was saved by home goalkeeper Kelle Roos.
Following a bright start the game slowed as both sides struggled to keep the ball but the Dons eventually made the breakthrough with their next chance in the 16th minute.
Coulson was the creator, winning the ball in midfield before sending Duk clear on goal and the Cape Verde international was calmness personified as he raced clear before slotting the ball past Jags goalkeeper Jamie Sneddon.
Duk took the spoils for the finish but it was Clarkson who went on to play a key role as the Dons surged forward looking for a second goal.
There were deft touches, clever passes and a long-range strike which flew just past post.
But the on-loan Liverpool man’s efforts eventually paid off with the second goal in the 31st minute.
His quick feet were too much for the Jags defence as he collected the ball in the box and whipped a ball across goal to Bojan Miovski who laid it off to Hayden Coulson.
The wing back’s effort looked to be going wide before it took a wicked deflection off Jags defender Kevin Holt into the net.
Partick were teetering and the Dons showed no mercy as they made it 3-0 three minutes later.
It was that man Coulson again as he raced into the box before beating Sneddon with the aid of another deflection to put his side firmly in control.
Miovski was desperate to get in on the act but he was denied by a terrific goal-line clearance from substitute Lee Hodson after Clarkson had unselfishly cut the ball back to him in the box as the Dons chased a fourth before the break.
In what had become a tough night for the visitors, who lost Muirhead early, Holt was stretchered off in first half stoppage time following lengthy treatment after colliding with a team-mate near the halfway line.
Early goal from Partick in second half
With Aberdeen three goals to the good Goodwin made a double change for the second half Clarkson and Miovski replaced by Christian Ramirez and Barron.
American striker Ramirez has been hardly seen so far this season but it took him all of two minutes for his first attempt at goal but his rising shot went over the crossbar.
Set plays looked Partick’s best chance at getting back into the tie and did pull a goal back in the 52nd minute when substitute Darren Brownlie headed Stuart Bannigan’s corner home to reduce the deficit.
The Dons responded with a well worked move which ended with Coulson playing in Ramirez but his shot was saved by Sneddon. Ramirez had another effort from long range but was again denied by the Jags goalkeeper.
Partick carried a far greater threat following their goal but did not test Roos and the Dons put the gloss on their win with a fine late goal as substitute Ryan Duncan cut in from the left wing before beating Sneddon with an angled drive to make it 4-1.
Aberdeen (3-5-2) – Roos 6, McCrorie 6, Stewart 6, Scales 6, Kennedy 6, Clarkson (Barron 46) 7, Ramadani 7, Besuijen (Duncan 78) 6, Coulson 7, Lopes (Morris 62) 6, Miovski (Ramirez 46) 5. Subs not used – Lewis, MacKenzie, Morrice, Watkins, Richardson, Milne.
Partick Thistle (4-2-3-1) – Sneddon 6, McMillan 6, Milne 6, Holt (Akinola 45) 4, Tiffoney (Brownlie 46) 5, Bannigan 6, Dowds (Graham 59) 6, Lawless 7, McKinnon 6, Muirhead (Hodson 23) 3, Docherty (Smith 59) 6. Subs not used – McCready, Weston, Mullen, Fitzpatrick.
Referee – David Munro 7.
Attendance – 9,323.
Man of the match – Hayden Coulson.
