Aberdeen boss Barry Robson questioned why VAR wasn’t used on a potential Dons penalty claim in the 1-0 loss at Rangers.
The Reds were left to regret two missed first-half chances by star striker Duk who recently scooped the club’s player of the year award.
However Robson was frustrated there was no VAR check when Duk was brought down at the edge of the box by Connor Goldson in the first half.
Goldson bundled the Cape Verde international to the pitch with the clash tied at 0-0 but referee John Beaton did not award a foul.
Robson wants to know why there was no VAR review on such a key moment.
He said: “In the first half is it a penalty or a free-kick outside the box?
“I don’t know but it’s one or the other.
“Where was VAR? Did anyone see it?
“Was it in the building today?
“I’m being serious, was it? Where was VAR?”
Asked if he talked with referee Beaton to raise his concerns, Robson said: “No. We are not allowed to do that either.
“I’m being serious.”
Aberdeen regret missed chances
Aberdeen’s red-hot winning streak finally ended courtesy of a volleyed goal from Todd Cantwell in the 64th minute.
It halted the Dons’ seven-game winning run, the club’s longest sequence of victories since 2015.
The Reds were also gunning for back-to-back wins against Rangers having recently beaten them 2-0 at Pittodrie.
Aberdeen had two glorious opportunities in the opening 45 minutes to go ahead at Ibrox, but both were spurned by Duk.
The 23-year-old has scored 18 goals in all competitions this season.
That form saw him complete a clean sweep of the club’s player of the year awards just three days before the Ibrox clash.
However, Duk had a 12-yard shot saved by Robby McCrorie and then chipped over from 20 yards when one-on-one with the keeper.
Robson said: “In the first half we should have scored a couple of goals.
“We had two brilliant chances to go a couple of goals up on Rangers.
“You have those two unbelievable one-on-one chances in the first half.
“You need to take them wherever you are, not just when you come to Ibrox.”
McCrorie undergoes hernia surgery
Aberdeen were minus midfielder/wing-back Ross McCrorie for the Ibrox clash.
Robson confirmed McCrorie has undergone surgery on a hernia problem.
He said: “He had a hernia injury so we had surgery but we are hoping to have him back pretty quick.”
Robson was confirmed as permanent manager recently when penning a two-year contract to lead the club until at least the end of the 2024-25 season.
Despite the winning streak ending Aberdeen remain in pole position to finish third in the Premiership.
The Dons did not lose any ground on fourth-placed Hearts who lost 2-0 to Premiership champions Celtic.
Aberdeen are five points ahead of Hearts with four post-split games remaining this season.
Robson said: “In the second half it was a poor goal to concede from us a set-play.
“I know Rangers had a couple of chances in the first-half with Kelle (Roos) making some good saves.
“But in the second half Kelle didn’t have a save to make.
“Rangers moved the ball about, as they do.
“There is the financial might and all the rest of it with the Old Firm and what they have.
“But I thought we were structurally very good and looked like we could open them up quickly at times.
“On another day it could have been a much different result.”
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