Caley Thistle clinched a 3-2 win at Hampden and a place in the May 30 final with Falkirk but only after referee Steven McLean and his officials missed a clear handball by Josh Meekings a yard off his own goal line as Leigh Griffiths looked to head home.
The Hoops were a goal ahead at the time of the incident which took place just before half-time and Parkhead manager Ronny Deila believes his side would have gone on to claim victory had the decision been given.
Striker Griffiths also claimed after the match that while arguing the call with McLean on the pitch, the referee said he had been informed by additional assistant referee Alan Muir - who was stationed just five yards away from the incident - that the ball had struck Meekings' face.
Now Celtic have asked for an official explanation after their supporters reacted with outrage to the decision.
A statement on the club's official website read: "With the Club being inundated today, Celtic can confirm that it has written to the SFA regarding yesterday's match and in particular the incident involving Leigh Griffiths and Josh Meekings
"First and foremost we absolutely congratulate Inverness Caledonian Thistle on reaching the Scottish Cup final
They are a fantastic club and reaching the final is a great achievement.
"However, given the level of reaction from our supporters and across football, we are duty bound to seek an understanding of what actually happened.
"We have not been given any other specific explanation so far and this is simply to understand the circumstances of what went on and why such an obvious error was made."
Source : PA
Source: PA