But, as he heads to Murrayfield tonight for the Hoops' crunch Champions League qualifier second leg against Legia Warsaw, could the Norwegian also be moving towards his Road to Damascus moment?
The ideals which travelled with Deila from Stromsgodset and which underpin his philosophy on football - performance based on tempo, passing and pressing - are all laudable.
But after just three competitive games in charge of Celtic, he must surely realise that, in this job, above all else, winning is what is demanded - of him and his players.
Success is not only the priority, it is the pre-requisite - never more so than through the twists and turns of the tricky qualification route to the Champions League Group Stage.
It is upon which Deila will be judged, whether that is fair or not, given that he is fresh in the door and overseeing a major transition at Celtic.
The remit handed to him when he agreed to succeed Neil Lennon was to win a fourth title in a row, continue to identify and develop talent which can be turned into profit and add any other domestic prizes along the way.
The club insist they do not budget for the fat cheque which comes along with qualification for the Group Stage of the Champions League, so it can't be something which is included in the job description.
However, the revenue generated by getting there in the past two seasons has more than made up for the £7million per year that Rangers' absence from the cross-hairs of Celtic was estimated to cost the Parkhead club.
And, while the Ibrox side try to battle their way up from the Championship to the top flight, Celtic's accounts do not want to show turnover falling back to just over £50m, where they generally sit in non- Champions League seasons.
Although prudent budgeting allied to success on the field and in the transfer market has placed the club on a very sound footing, such a prospect would be anathema to the men charged with controlling the club's finances.
So the fans who travel to Murrayfield tonight will not be the only ones praying that the players Deila selects can turn around the 4-1 defeat from the first leg in Warsaw.
A drop to the play-off round of the Europa League would mean that Continental football is still on the menu when the club finally returns to Celtic Park after the Commonwealth Games de-camp.
BUT the Champions League theme tune is not all that would be missing. The back-up competition yields only around an eighth of the money on offer in the main event - and, even then, that's only if you are successful and enjoy a run deep into the competition.
Add in the revenue lost when playing on Thursdays in the Europa League means domestic matches have to be switched from Saturday to Sunday, and the drop off in interest when the highs of Champions League nights are not there to punctuate the long dark run into winter, and the enormity of tonight's game starts to come into even sharper focus.
That interest also extends to players, prepared to endure 10 months of mainly-domestic action if they are receiving their regular fix of Champions League adrenaline, but who will re-evaluate their situation if that is removed for the season.
All of which will not have escaped the notice of Deila, who would also see his plans for making the squad improvements he has identified being shelved or having their plug pulled altogether.
Confirmed targets like Nancy's midfielder, Jeff Louis, would fall off the Hoops radar. The next time the Celtic fans hear the Haitian's name would be when he signed for a club they struggle to understand can compete with their own for players.
Above all that, though, turning round a three-goal deficit for the first time in the club's history would bring Deila that priceless commodity - time.
Sure, the play-off draw is on Friday, with the matches coming up on August 19/20 and 26/27. But by then the league season will be up and running, and the manager's system changes better understood and implemented.
The inherent danger associated with these games will not be removed, as Shakhter Karagandy reminded everyone by making the play-offs such a fraught affair 12 months ago.
But a major test of character and credibility will have been passed, and Deila's credentials will have been franked.
Should he not manage to succeed in plotting a comeback from the woeful Warsaw performance and result, the rush to judgement which has already began will pick up pace.