David Martindale admits he was baffled by the decision to allow Rangers' opening goal against Livingston last night.
Abdallah Sima was played down the left channel by Ridvan Yilmaz during the first half.
As the attacker looked to get in-behind the Lions' defence, he bundled defender Jamie Brandon over to the deck, before racing in on goal and finishing superbly from a tight angle.
Willie Collum opted not to award a foul for the situation, while VAR Nick Walsh also saw no reason to intervene with a review of the goal.
Fans and pundits have since been left perplexed by the situation, with Sima appearing to push Brandon in order to break away with the ball.
Speaking after the 4-0 loss, Martindale insists the decision was a bitter one to take.
"I think the first goal is a foul, I've watched it back myself, there are clear hands on and it's a push - not a huge one - but when you're running with momentum and get a push you are going to fall," he told BBC Scotland.
"For the life of me I don't know how we haven't got a foul...the first goal hurts us, it spooks us. I'm disappointed because as it went to VAR review it was in the phase of play that led to the goal, my understanding was it doesn't have to be clear and obvious if it leads to taking the ball and putting it in the back of your net. I thought it would get overturned, and it never.
"I don't think anyone goes out to make bad decisions, so we've got the technology but it comes down to the opinions of people making the decisions. Some times the decisions fall your way, sometimes they don't.
"Ibrox away, quarter-final, pfft...I've not seen many of them given to be honest. No officials go out to get it wrong, but I can't believe it's not a foul. I'll not be contacting anyone."
Sima scored another in the match while Yilmaz and Ryan Jack also got in on the act to set up a semi-final with Hearts in November.
