Celtic manager Neil Lennon questioned the quality of refereeing in Scotland after some controversial decisions marred his side's 1-1 draw away to St Mirren.
Kris Commons had headed the Hoops into a sixth-minute lead but St Mirren responded brightly before Gary Teale's effort was disallowed for what looked to be a soft foul on keeper Fraser Forster by Paul Dummett.
The home support were further incensed when referee Bobby Madden and his assistants failed to spot Georgios Samaras using his arm to control Teale's corner in the box on the stroke of half time.
The second half was barely 10 minutes old when Kenyan international Victor Wanyama, in his first match back following a suspension, was shown a straight red for a clumsy challenge on Paul McGowan, which looked harsh.
Time appeared to be running out for St Mirren as they looked for an equaliser but another big decision from ref Madden put his performance in the spotlight. There was a hint of a dive as Esmael Goncalves went down after Emilio Izaguirre tried to prevent him breaking into the box but, regardless, the challenge took place outside the box.
McGowan drilled the spot kick beyond Forster to claim a point and after the game a clearly furious Lennon, who has a three-match suspended touchline ban hanging over him after a tirade against referee Willie Collum in last season?s Scottish Cup semi-final defeat, couldn't hide his frustrations.
"I have to be careful about what I say really as I have a suspended sentence hanging over my head but that was by far the most appalling refereeing performance I have seen this season by a long way," Lennon fumed.
"And it was for both sides. It was a clear penalty for St Mirren in the first half as Samaras has handled the ball and how he doesn't see that and the linesman doesn't see it I don't know.
"His decisions today were just baffling. It was never a red card for Wanyama and it was never a penalty for St Mirren in the second half. It was outside the box and there was no contact.
"How he got so many big decisions wrong in one day is beyond me. I haven't said anything insulting and I'm not calling the referee's competency into question, I just thought he had an appalling game.
"We have been pretty concerned now for the past couple of months now about the abhorrent decisions I've seen, not just against my team, but in general in the Scottish game.
"So I am pretty concerned about the level of refereeing at the minute in this country."
It was the first time St Mirren have scored in over 13 hours of league action against the Hoops and halted a run of eight straight defeats against the Parkhead side.
But Lennon said the refereeing performance would overshadow the good football on show at times from the two teams.
"We started the game well and then St Mirren came back into it strongly," Lennon admitted.
"There were a lot of good players out there. St Mirren were playing with a bit of freedom after winning the (league) cup and made it really competitive.
"It was tough and there was good football but the sending off totally killed the game as a spectacle really.
"Our ball retention should have been better even with the ten men but we are going to be talking about the referee rather than the competitive nature of two good footballing teams."
Celtic still increased their lead to 13 points and could clinch the championship next Saturday with a win at home at Hibernian if Motherwell lose to St Mirren.