Manchester United were awarded a penalty when Matheus Cunha went down under the attention of Crystal Palace defender Maxence Lacroix.
After a lengthy VAR check, the referee pointed to the spot and showed Lacroix a red card. His challenge started outside of the box, before carrying on inside the area.
McCoist wasn't having that call, dismissing the notion that United should've had a penalty in the first place.
And it was here that he used the airwaves to reference the challenge on Mikey Moore by Cammy Kerr on the edge of the box during last week's 2-2 draw at Almondvale.
“I saw the goals when I was doing my bits and pieces but I did not see the red card at Old Trafford," he said on talkSPORT. “That is absolutely outrageous.
“The week before, the Rangers incident, they’re telling me the foul starts outside of the box and then nothing happens.
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“So it’s a foul Rangers don’t get and the boy could be sent off. The complete opposite happens in that one (Lacroix). It’s not even a foul.
“What is the ref seeing? Cunha throws his arm back as if he’s been shot. I hate it.
“You go back a week earlier and the full-back smashes Mikey Moore and it’s play on.
“He has given a penalty there (at Old Trafford) and it’s not even inside the box!”