Former Northern Ireland team-mates Neil Lennon and Steve Lomas found themselves at odds over two major incidents as Celtic lifted themselves to within four points of leaders Rangers with their seventh straight SPL win.
St Johnstone manager Steve Lomas questioned the honesty of Daniel Majstorovic's challenge on David Robertson on the half-hour, which saw both players go off and left the Sweden international with a suspected fractured cheekbone and eye socket.
Lomas also claimed Hoops midfielder Beram Kayal should have been sent off after the break for charging down Liam Craig's free kick after being booked by referee Euan Norris for doing it the first time.
Celtic broke for Ki Sung-yueng to score Celtic's second goal, adding to Gary Hooper's opener, and leaving Lomas fuming.
The Saints manager claimed Norris's refusal to take action against Kayal was a turning point.
He said: "The guy got booked and then the second time he was four yards away before our player even struck it. We went to sleep and they scored on the counter, which made it comfortable for them. I don't want boys sent off but rules are rules.
"I could see it from where I was at. Maybe he [the referee] didn't see it but if he has booked him once, you would like to think he is looking the second time.
"Obviously he has to make a big decision, hasn't he? Maybe you don't get those decisions against Celtic."
However, Celtic manager Lennon said: "I don't think it deserved a booking the second time.
"The Majstorovic challenge was a perfectly good, full-blooded challenge from a centre-half who only had eyes for the ball and ended up worse off for his own bravery.
"There was nothing wrong with the challenge at all. It looks like a fractured cheekbone and it could be a fractured eye socket as well. It is a big blow because he has been immense for us."
Lomas, who was "proud" of his side's performance, saw Majstorovic's challenge differently. He said: "It might have just been an honest collision but I wouldn't bet my house on it."
Saints keeper Peter Enckelman had made two great saves from Hooper before the former Scunthorpe striker broke the deadlock on the hour from a yard out following a corner. Four minutes later Ki scored on the break to seal the win.
If Majstorovic's injury is as serious as first feared, it will rule him out of the visit of Kilmarnock next Saturday and what is shaping up to be a crucial Old Firm derby against Rangers at Parkhead on 28 December.Reuse content