AS the Inverness Caledonian Thistle players celebrated in front of their astonished and delighted supporters, the Celtic team almost to a man went over to referee Steven McLean and his colleagues to have a not so quiet word.

You needn't have watched the previous 120 and more minutes to wager a guess at how this semi-final had been decided, certainly in the minds of those wearing green and white and their own fans.

There was plenty to talk about at Hampden Park, but it would be remiss not to start by congratulating John Hughes and his side who made the most of some good fortune and the fact Celtic were reduced to ten men when Craig Gordon was sent off in the second half.

A cup final last season and another to come where they will be serious favourites to beat Falkirk is a superb return for Hughes, a talented and under-rated manager. His team played well and scored three goals. They did all they needed to do and more.

But - and this is a 'but' you can see from space - the entire match hinged on one of the worst decisions by an official the old bowl in Mount Florida has ever witnessed.

The official Twitter account of Inverness Caley Thistle was an entertaining read. The tweet of the day read: "Apparently Meekings shouted 'I'm in nets' when the ball came in so it's not a penalty."

Even those who work for the Highland club recognised what had happened before half-time. A header from Leigh Griffiths was going into the goal until Josh Meekings stretched out an arm and stopped the ball.

It was a penalty and a red card. No question. Yet, referee Steven McLean didn't see it that way, he will claim he didn't see it at all, but that's okay because Alan Muir, one of those additional assistants who hang around behind the goal like someone lurking on the fringes of a conversation they are not invited to, was only yards from the incident.

He was sure to have spotted it. After all, that is what he is there for. Nothing else. Oh. Right.

There are mistakes made by officials every week, but this really was a corker.

At 2-0 and a man down, it would probably have been game over for Inverness and Celtic were going to win a treble for Ronny Deila in his first season as manager.

But Muir's mistake - he apparently thought the ball had hit the face of Meekings - gave Inverness a lifeline, one that they took with aplomb. When Marley Watkins was brought down by Gordon, this time the referee got the penalty and red-card decisions right, Greg Tansey scored and the men from the north took control of the game.

It went to extra-time. Edward Ofere scored in the first half to put Inverness ahead, John Guidetti's free-kick deceived goalkeeper Ryan Esson for an equaliser that hadn't looked on the cards, but just when Celtic felt they had taken the game to penalties, David Raven popped up at the back post to touch home a cross from the best player on the pitch, Graeme Shinnie.

The smile on the face of Hughes was in stark contrast to his counterpart Deila, who must have wondered what he had done to deserve such rotten luck.

Before kick-off, as his players went through their pre-match routine, Hughes wandered over to the away fans to say hello. The reception awarded to him highlighted what he has done for this football club in 18 months.

If he can guide Inverness to third place in the Scottish Premiership, win a Scottish Cup and therefore take the club into Europe for the first time, then there is a debate to be had whether he should be manager of the year rather than Deila.

The Norwegian's standpoint all season was that trebles were not an easy thing to win because anything could happen to scupper the process. Boy, was he right.