Celtic boss Ronny Deila hit out at Kris Commons after the midfielder threw a fit at being substituted in the 3-1 Europa League defeat by Molde in Norway.
In dreadful conditions at the Aker Stadion, first-half goals by striker Ola Kamara and defender Vegard Forren gave the home side a two-goal interval lead.
Commons reduced the lead in the 54th minute with a well-taken goal but seconds later Mohamed Elyounoussi restored the Norwegian club's advantage.
When the former Derby attacker was replaced by Nadir Ciftci with 15 minutes remaining he showed his rage as he went into the dugout, appearing to shout at assistant boss John Collins.
Deila said: "That is not acceptable. We are a team. I can understand that players can be disappointed getting taken off but to show it that way is not how we want to have it at Celtic.
"We are one team and it is not about one player. It was very disrespectful to every one of us.
"He was talking to everybody. He was irritated he was taken off, that's okay but you do it a better way than he did it tonight
"I have spoken to him, of course."
Deila explained his decision to take Commons off was a matter of balance, as Ciftci went up in attack to partner Leigh Griffiths.
"It is always a matter of having the balance between attacking and defending," said the Norwegian. "You can't only have four strikers, you need to have somebody who can defend as well, so we can have the ball.
"We wanted two strikers on and we needed more balance in the midfield because you saw that when they got the ball they counter-attacked us.
"There is a number of games coming up and Kris can be important in them as well."
The Parkhead club are bottom of Group A with two points from three games ahead of the visit of the Norwegians next month.
Deila said: "It makes it much harder but we have two home games now.
"There is still a chance but we need to win against Molde at home and also Ajax at home and then we will see what kind of position we are in I am very disappointed. We didn't perform at the level we should do.
We started OKand then they scored, we got stressed and were uncomfortable on the ball. We didn't get behind them, not enough crosses and the game went the way they wanted it to, on the counter attack.
"The first goal is important, they could stand back and wait for us but we should have created more. We got to 2-1 and then conceded an easy goal and then it was very difficult. We were not switched on enough and everything went too slow. I expected a much better performance."
It was Ole Gunnar Solskjaer's first official game as boss of the home side following his return to the club for the second time on Wednesday.
But the former Manchester United striker took something of a back seat, going with the team already picked by Erling Moe, who had been in caretaker charge since Tor Ole Skullerud was sacked in August.
Afterwards Solskjaer said: "It was difficult conditions, which made it not the best of games.
"They had more possession but we defended really well
"Three more points will get us through and we have three big games coming up."