Ross County manager Malky Mackay questioned the lateness of Celtic’s stoppage time winner at Victoria Park.
Anthony Ralston’s headed winner came after the six indicated minutes of additional time had been played.
The Staggies had looked certain to secure a point against the 10-man Hoops, after Jack Baldwin had cancelled out Liel Abada’s first-half opener.
After suffering defeat in the most agonising of circumstances, Mackay expressed his disappointment that referee Alan Muir permitted enough time for Celtic to make the breakthrough.
Mackay said: “I don’t want to ask the referee anything, otherwise that’s going to cause me problems and put me into trouble if I say one more word to him.
“Where they got seven minutes from is an interesting one. At one point it felt as if we were playing until they scored.
“But for the ball coming off Dom Samuel’s head, the shot in the last second of the game was going into the top of that stand. It’s fine lines, but I think you saw how relieved Celtic were leaving here.
“It’s a measure of where Ross County have come this season that we are running the Old Firm as close as that.”
The defeat is only County’s second from their last seven games, with their last loss coming against champions Rangers at Ibrox.
County remain 11th in the table, on goal difference above St Johnstone.
Mackay was full of praise for the way his side stood up to the challenge of facing Ange Postecoglou’s men.
He added: “I’m proud that our players enacted the gameplan, and ran Celtic as close as they did.
“You could hear with the celebrations they were lucky to get away with the three points.
“I look at the progression we’ve had since day one of the season, where we are taking on the Old Firm toe-toe-toe. The two defeats we have had recently have been against both of them, but we are scoring against them. We knew we could hurt Celtic.
“At half-time we wanted to step up and press them high, which is what we did. That got us the goal and the sending off.
“To a man, I gave them credit for doing exactly what was asked of them and put bodies on the line.”
