It has. Just not in the manner anybody could possibly have foreseen.
The Champions League was meant to be the difficult part. Celtic were expected to compete valiantly against Barcelona, Benfica and Spartak Moscow but be left fighting for third spot at best. Instead, they have taken themselves to the cusp of qualification for the last 16.
The league, by contrast, was meant to be a walk in the park. With no Rangers to offer meaningful competition, it was anticipated that the annual two-horse race would be replaced by the one remaining thoroughbred galloping miles ahead of the 11 carthorses. It could be the first league championship to be decided by Christmas.
And yet -
Celtic still top the Clydesdale Bank Premier League but they have looked far from comfortable in getting there. Saturday's defeat by Inverness Caledonian Thistle, courtesy of Billy McKay's second-half goal, was their third loss in the league this season. Throw in four draws and it means Celtic have won only half of their 14 games. They had accrued more points by this stage last season – a period when manager Neil Lennon's job was thought to be seriously under threat – and have not started this poorly in the league since 1998/99.
There is an argument that were it not for the Champions League – especially the win over Barcelona – then Lennon would again be feeling a bit of heat.
The counter argument to that is were Celtic not playing such high-stakes European football every fortnight, then they would almost certainly be showing far greater consistency in the league.
It may also be in the back of the Celtic players' minds that, with no "genuine competition" for the title, they do not need to be anywhere near as efficient as in previous seasons. That Lennon's side still lead the division with a game in hand demonstrates that none of the others has the consistency to mount a serious challenge.
Celtic could probably operate at two-thirds capacity between now and May and still retain their championship.
Lennon has delivered for Celtic in Europe this season but that has not ensured immunity from criticism. Towards the end of Saturday's game, with his team again huffing and puffing, the Northern Irishman became embroiled in an altercation with some supporters behind his dug-out. They weren't happy with him, or his team, Lennon later revealed, and he, in turn, told them he would resign if they felt he wasn't the man to take the club forward.
"If the fans make it clear they are not happy and they want me out, that's okay," he said afterwards, clearly still riled by the whole thing. "I will do the honourable thing."
It will surely not come to that. The hope for Celtic is that, once the final Champions League group game, against Spartak Moscow, is out of the way, they will start to regain some sort of consistency. For now, though, they are floundering in their league games, especially at home. This was another lethargic, flat performance. Too many players were off form. Nothing Kris Commons tried came off for him, while Georgios Samaras twice in the first half allowed the ball to escape from his possession and dribble out embarrassingly for goal kicks.
"Our play in the final third wasn't good enough," admitted Lennon." The back four were fine and I felt [Biram] Kayal had a good game. But our final ball, crossing and shots weren't good enough. If you can't keep clean sheets and keep missing easy chances like that, then you're liable to be beaten."
These are magical times for Terry Butcher and Inverness Caledonian Thistle as they chalk up milestone after milestone. This was Butcher's first win at Celtic Park as a manager, his club's first ever league win there, and the first time Inverness had defeated both Rangers and Celtic away from home in the same season.
"We've created history for the club with our first ever SPL win here, we're creating history all the time this season, and that's what we intend to keep doing," said Butcher.