Ross County boss Jim McIntyre sought an explanation from referee Willie Collum after home goalkeeper Craig Gordon survived a possible red card in Celtic's 2-0 win over the Staggies at Parkhead.
The most controversial moment of the Ladbrokes Premiership curtain-raiser came in the 22nd minute with the home side leading through an early Leigh Griffiths penalty.
Hoops fans held their breath after the Scotland goalkeeper fouled former Celt, Jackson Irvine, in a 'last man' challenge outside the box.
However, Collum only showed Gordon a yellow card and, when midfielder Stefan Johansen made it 2-0 before the break, it effectively sealed the win for the champions.
Afterwards McIntyre went to see the official to seek answers before making his way to the post-match media conference.
He said: "It is a goal-scoring opportunity.
"But Willie felt it wasn't an obvious goal-scoring opportunity, and that is the wording of the law.
"And if the referee doesn't feel that, he can't give it. So I have to grin and bear it.
"I certainly think Virgil van Dijk was getting round so I am not sure it is a red card, but Jackson could have got on to the ball and scored.
"It was a sore one because it would have been interesting if we had managed to get that."
Hoops boss Ronny Deila was non-committal, saying: "It was a tough decision. I need to see it again.
"I can understand Ross County's thinking in that situation.
"It is hard for the ref and hard for us who were watching. I don't know if it is right or wrong."
Deila was more confident in his belief that Griffiths will be fit for the second leg of Celtic's crunch Champions League qualifier against Qarabag on Wednesday night.
There was concern inside Celtic Park when the Hoops striker came off with a knock in the 19th minute to be replaced by Stefan Scepovic.
The Scottish champions take a 1-0 lead over to Azerbaijan as they bid to reach the play-off stage, and the Celtic boss believes Griffiths will be ready.
"I don't think it is serious," the Norwegian said. "I think he will be back for Wednesday.
"It is nothing pulled - it is just a knock.
"I didn't know if he had twisted his ankle or whatever, but it seems it is just a knock in the calf muscle and hopefully he will be ready for Wednesday."
Deila has preferred summer signing Nadir Ciftci to Griffiths since the start of the season.
However, the former Dundee United striker was suspended, allowing last season's top scorer the chance to notch from the spot after only four minutes when he was brought down in the box by Dingwall skipper Andrew Davies.
"He only needs three or four minutes to score - that is good," Deila joked.
"He will get a lot of playing time - that is no problem. We need all our players."
Deila was delighted with 18-year-old Kieran Tierney, who made his home debut in the absence of suspended Emilio Izaguirre and Charlie Mulgrew, out with a knee problem, before making way for debutant Saidy Janko in the 63rd minute.
"I am very satisfied with him," he said. "He is a talented player - he just needs to get the stamina to go 90 minutes instead of 60.
"We are not 100 per cent sure yet about Charlie. We will see if he is back Wednesday or Saturday."
Deila was not totally satisfied with the performance, saying: "The last 30 minutes was sloppy and messy,
"We were not together as a team. W e lost the ball all over the pitch and that was disappointing."
Striker Anthony Stokes, who did not feature but was part of the 20-man squad, was reportedly told by Deila this week that he did not have a long-term future at the club, but t he former Stromsgodset boss denied that had happened.
"I have never told Stokesy that," he said.
"He is part of this team. He has to work really hard to get into the squad and into the team.
"There is big competition and there is always someone who is disappointed, and now it is Stokesy."
Source: PA
