Former referee Bobby Madden reckons St Mirren were denied a clear penalty in their 1-0 loss to Rangers.
The Paisley club fell to a last-minute Bojan Miovski strike as they left Ibrox without anything to show for their performance.
However, ex-ref Madden reckons St Mirren should have had a spot-kick in the first half after Ismeal Kabia was felled in the box.
The winger had played the ball before Emmanuel Fernandez made contact with his foot inside the area.
Appeals for a penalty were waved away with no VAR intervention over the incident, when the scores were level.
Posting on Instagram, Madden explained the reasoning for a penalty as he referenced the 'Clear Lines' guidance for referees.
He said: "This will be a highly controversial decision in the match between St Mirren and Rangers.
"You can see the attacker plays the ball away from the defender who comes in late and steps on the foot of the attacker.
"We need to consider what UEFA's new platform 'Clear Lines' says about such situations.
"A direct free-kick is awarded if a player shows a lack of consideration, careless or a disregard for his opponent, reckless.
"Clear Lines states that there should be a penalty awarded or VAR intervention if the step on foot is clear, if there is a significant degree of intensity and if it impacts on the attacker."
The UEFA portal provides references of instances where a penalty should be awarded, while also explaining if the defender plays the ball before natural following contact then no spot-kick would be given.
Madden continued: "If a defender plays the ball and the subsequent action is considered normal for that movement, a penalty wouldn't be awarded.
"In this case, the defender didn't play the ball, so there is no reason why a penalty kick was not awarded."
