The lung-bursting effort to get to the winter break is over. A couple of weeks to relax before starting the search for a second wind can now begin.
Knowing that there is going to be some much-needed down time halfway through a testing campaign can be a psychological barrier before it actually becomes a respite.
Players know it is built into the schedule and begin to believe that, the closer they get to it, the more they need it. Hence the kind of jaded performances which have made the last couple of games such a struggle.
The 1-0 defeat to Hibs at the end of 2012 was followed by a 1-0 win over Motherwell in the first match of 2013.
The symmetry was not what manager Neil Lennon wanted. Two comprehensive victories was what he demanded.
And, though the win over the Steelmen – courtesy of Gary Hooper's 18th goal of the season 11 minutes from time, and just three minutes after Fraser Forster had saved a Tom Hateley penalty – sees Celtic go into the break having extended their lead in the SPL championship to nine points, the manager will be more relieved than satisfied.
He wasted no time after the final whistle blew to head for the airport on a secret mission, presumably to update himself on some potential signing target.
So it was left to coach Garry Parker to rake over the bones of what provided an exciting 90 minutes, given that the result was in doubt for the vast majority of them.
"It was very important that we did not go into the break with back-to-back defeats," he said.
"Losing to Hibs was a big blow to us, and we said to the lads before the game that this was like a cup final. We needed to win and get nine points clear with a game in hand over most of the other teams.
"They responded to that, and the win was massive for us. Now we can go away and recharge the batteries and come back ready for the Hearts game on January 19."
Against Motherwell, Celtic had started like a train, getting up a head of steam, but just as quickly hitting the buffers without a goal to show for their efforts.
Parker admitted the men in charge were concerned that their domination had not been converted into something tangible.
He said: "You always worry when you have a start like that, but don't get a goal. We were frustrated on the sidelines.
"We had 18 attempts on goal during the game, 10 of them on target, and you never think it is going to go in for you. But Gary came up trumps again and scored a good goal."
The pace and purpose was always there, particularly from men like Hooper, who seemed pleased to have Kris Commons back in the side to provide the ammunition after a month out through injury.
But without Scott Brown in midfield – his hip condition returning with enough growl to rule him out once again – there was no one to lead, organise and drive when Motherwell found themselves weathering the early storm and gaining a foothold in the match.
Indeed, as the second half progressed, the acres of space in which the likes of Keith Lasley and Jamie Murphy – in what was his last game for the club before moving to Sheffield United – found themselves as they helped turn defence into attack was alarming.
The legs and lungs of the Celtic players were screaming – as were the coaches and manager in the home dugout.
It was one of those tired limbs, belonging to Kelvin Wilson, which drew a penalty as he brought down the twisting and turning Murphy.
But with Forster incensed by the fact Hateley had placed the ball ahead of the spot, though just covering it to stay within the rules, the flying save which pushed the ball for a corner should have come as no surprise to anyone.
With the stadium finally energised, neither should have the goal for Celtic which quickly followed.
Commons carried the ball to the centre line, before passing to Hooper, who laid it off to Georgios Samaras.
A burst by the Greek down the left wing was followed by the perfect delivery into the middle where Hooper, who had given every last ounce of energy to get ahead of his marker, slid his shot home.
It might take the top scorer the best part of his two-week sabbatical to catch his breath after that effort, but he can do so with a contented smile on his face.
As can all his team-mates. The major staging post has been reached, the best part of the season has still to come.
Perhaps the giant screens behind each goal advertising the home leg of the Champions League last-16 match against Juventus was a distraction to those on the field.
But it can now be a massive incentive, because no-one will want to miss out on the most important game played at Parkhead since Barcelona were here at the same stage in 2008.
For that challenge, Celtic will have to reproduce their very best form from the first half of the season, something which has not been seen for the four weeks since qualification was achieved.
Lennon and his backroom team can only hope the 17 days without a game will work the oracle.