AS Ronny Deila sat down with the Scottish press to detail his plans for a decade-long dynasty at Celtic at the weekend, little did the Parkhead manager know that the first bump in the road was lurking ominously just around the corner.

His proclamation that he wished to be in charge of the Scottish champions for at least 10 years was all the talk as Celtic supporters travelled on Sunday morning to Hampden for their William Hill Scottish Cup semi-final with Inverness Caledonian Thistle. By the time the tie was done, it couldn't have been further from their minds.

The Celtic manager, and countless members of his squad, have gone on record throughout this campaign about their ambitions and one word has repeatedly come up: Treble. It is a statement of ruthless ambition that is the embodiment of everything the Norwegian is trying to instil at a club that measures success in trophies. One was already in the bag in the form of the League Cup, the Scottish Premiership appears to be Celtic's barring a minor miracle for Aberdeen and the William Hill Scottish Cup was just two more wins away. It is understandable then that hopes were high that Deila could go one better than his predecessor Neil Lennon and record an historic hat-trick of silverware only ever achieved by two managers in the club's history.

However, the defeat to Inverness, a team two places and 21 points below them in the league, will provide a constant reminder of not just what could have been, but exactly what must be corrected to make sure that treble ambition is realised, whether next year or in the nine after that.

Of course, it is impossible to lay the blame for this season's failed attempt solely at the door of his players. Sunday's game was an encounter that will be talked about for many years to come as one of the most contentious and controversial Scottish Cup contests in living memory, but perhaps for all the wrong reasons. Despite the drama, momentum swings and goals, for most who shuffled angrily out of Hampden it was all about one moment just seconds before half-time. A handball not seen, a penalty not awarded, a red card not flashed, a moment to kill a game off not offered up.

The consternation among the Celtic players too in the immediate aftermath was also clear to see. At the end of the match a group of them protested furiously to referee Steven McLean, with Virgil van Dijk receiving a caution for his trouble. While their outpouring of emotion told its own story on the park, the silence in the post-match mixed zone - an area only three of Deila's squad could stomach dissecting what had just happened in - was deafening.

Yet, it is important to remember the position the Norwegian's team were in at the point of impact - that is when the ball impacted squarely off of Josh Meekings' wrist. Celtic were a goal to the good and had rarely been troubled at the other end despite Inverness' advances. This was not a match slipping away from them, this was a game still firmly within their control.

It took just nine minutes of a second half for it to slip away as Craig Gordon was rightly sent off after being badly exposed by his defence who allowed Marley Watkins to race through on goal to eventually get clattered by the Celtic goalkeeper. From then on in it was always going to be an uphill task, but it was a challenge a squad laden with talent, depth and experience laboured with. Celtic's mentality and how they reacted to not getting a decision was always going to be the key factor on Sunday, and arguably they allowed their emotions to get the better of them and Inverness, rightly or wrongly, took full advantage. As they gather themselves and get ready to go again tomorrow, in Premiership action against Dundee, the importance of not letting their sense of injustice linger is of paramount importance.

"It is hard to speak now after Inverness have won. It's in the past and we must now work up the mentality now to win the league," admitted Emilio Izaguirre, the Celtic left-back. "Now it's finished for the treble. We'll try our best to win the league and next season we'll try and win the treble. Now it's finished, everything is finished and we must try our best to win the league."

Deila's dynasty has been derailed. It is now up to him and his team to make sure they get back on track tomorrow.