Celtic manager Neil Lennon has described the performance of referee Bobby Madden during the Hoops' 1-1 draw with St Mirren as "appalling".
St Mirren then had a strong penalty appeal turned down when the ball appeared to hit the arm of Celtic captain Georgios Samaras.
Victor Wanyama was shown a straight red card early in the second half for a challenge on Paul McGowan, who then levelled the game from the penalty spot with 10 minutes remaining, after Emilio Izaguirre was adjudged to have fouled Esmael Goncalves.
"That was the most appalling refereeing performance I have seen for a long, long time," said Lennon. "I mean, you can't get so many big decisions so wrong, it is incredible.
"For me St Mirren should have had a penalty, it is a clear handball. You don't get many more as clean-cut as that so we dodged a bullet there.
"Then I see Kayal getting wrestled into the advertising hoardings right in front of the linesman and he doesn't give a free kick and, two seconds later, I've got a man sent off for nothing and the penalty that St Mirren did get was outside the box and there is no contact."
Lennon went on to confirm that he plans to appeal against Wanyama's red card.