As 2013 dawned, expectation was building - uncontrollably, and unrealistically - that the upcoming Champions League last-16 ties against Juventus were not going to be the glass ceiling for the Hoops in the competition.
Instead, the roof caved in with a 3-0 home defeat in the first leg, quickly followed by a 2-0 polish off by the Italians back on their own patch.
However, there would be a further dozen European games for Neil Lennon and his Bhoys before the year was out.
Four qualifiers followed by two play-off matches and then six group stage games must have felt like a mini-season all on its own, given the pressure such matches place on minds and resources.
So it can't be overstated what an achievement it was for Lennon to claim his second successive league title, and his first Scottish Cup/League double, then pushing on to place his side in a seemingly-unassailable position to clinch three-in-a-row as they turn into 2014.
The consistency shown in the SPFL Premiership is in stark contrast to that shown in the first half of last season's campaign, unbeaten after 18 matches and 11 points clear.
The League Cup exit at the hands of Morton in September was the major blip, but also provided the shock to the system which has since kept the Hoops on the correct course for more silverware a few months from now.
In the year about to end, Celtic played a total of 57 games across four different competitions, including 14 in the Champions League.
They won 37 of these games, drew seven and lost 13, that final figure much-inflated by competing in Europe's elite competition, starting with those last-16 ties.
Lennon's pride in all of this is clear - and understandable - not least because his side has been shorn of three very important players in Gary Hooper, Victor Wanyama and Kelvin Wilson.
The last named has been more than adequately replaced by Virgil van Dijk, the best signing made by the club this year, indeed, since Wanyama was acquired from Beerschot for just £900,000.
However, the plan was to pair Wilson and van Dijk together at the heart of the defence, with Ambrose either moving to the side or into midfield.
Flexibility and the need to adapt has been at the nub of Lennon's period in charge, and, with experience, he is proving more adept at it.
Lennon knows more of the same will be required. As a new year dawns, the challenges and demands remain the same.
To this end, the Celtic boss is planning a very active opening month while the transfer market is open, and targets identified over the past few weeks will now be perused with serious vigour.
It will put extra strain on a man who is already feeling the mental and physical effects of a draining campaign.
But with so much at stake in the long term, Lennon is more than prepared to summon up the energy to keep going, and demands his players do the same.
He said: "I wouldn't say we are all feeling a little bit tired, but it has been a real tough first half to the season. Look, don't get me wrong, you want to be involved.
"But it just seems to have been non-stop for the players. Some of them are into their 33rd game for us this season. It takes a huge, huge effort.
"And to be unbeaten in the league at this stage of the season, no matter how many games you have played, is fantastic.
"The clean sheets are now coming. At Inverness it was our sixth in a row domestically, and I think that means we are close to a record for the club."
Strangely, it was only in the last week that the Hoops were finally able to lay claim to the best defensive record in the Premiership, Fraser Forster's frugality carrying them clear of the likes of Dundee United and Inverness, the long-time league meanies.
At the other end, the need for a clinical finisher to put away the copious chances his side creates has never been more apparent, the 1-0 and 2-0 victories replacing the short burst of five and seven-goal trouncings which heralded the dawning of December.
Lennon wants his players to be better rewarded, in terms of goals, for the effort they are putting in.
And he wants the fans who have stuck by them when the title already looks to be in the bag, to be entertained and have something more to cheer.
"I just need us to be a little bit more prolific in front of goal," said Lennon in an amalgam of a belated Christmas wish and a new year resolution.
"That's not a major issue for me at the minute," he continued. "We have always scored goals and we have proved that in this calendar year."
That was a proud reference to the fact his side found the net in every league game played in 2013.
In total, Celtic played 36 SPL and SPFL matches, winning 27, drawing six, and losing only three, the last of which was against Motherwell on April 28, immediately after the 2012-13 title had been wrapped up in green ribbons and placed in the Parkhead trophy cabinet.
This season, they have won 15 of their opening 18 SPFL games, drawing the other three. That gives them a points total of 48 from a possible 54. For the calendar year, it was 87 points from a possible 108, title- winning form in anyone's book.
For all the hype which surrounds the Champions League - and the money that helps retain the focus very much on it - it is the league championship which remains the No.1 priority for Celtic.
Without success in it, the chance to contest the qualifiers for the Champions League disappears.
With that would go approximately a third of the club's potential turnover for the year and, as a consequence, a large chunk of the transfer budget afforded to Lennon.
Minus that investment, the quality of player he can attract would be compromised.
So, while an early conclusion to the league race might not suit the TV channels, who would like to see a real challenge sustained by at least one of the chasing pack until after the split, the sooner it is all done and dusted, the happier Lennon will be.
As 2014 prepares to be welcomed, he is already making plans for next season, a necessity rather than an over- confidence, given how early the qualifiers come back around.