Since the night in December 2012, when Kris Commons' late penalty against Spartak Moscow took Celtic into the knockout round of the Champions League, the club's problem has not been so much making similar progress in the competition. First of all, it's about getting there.
In the following 11 seasons, the Parkhead club only got into the European elite five times in the group stage.
The names of those whose challenges proved insurmountable in the qualifying rounds would hardly be included among the European elite: Maribor, Malmo, AEK Athens, Cluj, Ferencvaros and Midtjylland.
In the years in which that hurdle was overcome, only once, in the 2017-18 season, did Celtic avoid the ignominy of finishing last in their group.
Celtic could talk about being a Champions League club but, when their attendance record and performances over a long period did not match the claim, the talk rang hollow.
There has been no big secret as to why the club has been below capacity in that period.
Adam Idah returned some of his £8.5million transfer fee by forcing the winning goal against Young Boys.
Winger Nicolas Kuhn has shown the quality that Brendan Rodgers needed in his new signings
Kasper Schmeichel has shown that Celtic can still find bargains in the transfer market
A transfer strategy that relied too much on spotting bargains inevitably led to a series of managers working with teams that had star quality but were packed with too many mediocre players.
While companies such as Commons, with £300,000, or Virgil van Dijk, with £2.6 million, were outstanding pieces of business, a large number of players arrived for modest fees and left without having made an appreciable impact.
When Brendan Rodgers returned to the club in 2023, there was some evidence of a change of direction.
Under Ange Postecoglou, the club had spent £4.5m on Kyogo Furuhashi, £4m on Carl Starfelt, £6m on Cameron Carter-Vickers and £6m on Jota.
The £1.5m spent to sign Matt O'Riley and the £1.4m to sign Reo Hatate showed there were still cuts to be made. The danger was in assuming that the club would strike gold every time.
Rodgers' first transfer window for the second time brought to mind the old saying about having to kiss a lot of frogs to find a prince.
Among the nine signings were Odin Thiago Holm, Marco Tilio and Kwon Hyeok-kyu. With a team lacking any real depth, Celtic racked up four points and a multitude of hard luck stories in the Champions League last year.
When the January window opened, Rodgers made his position clear. If he couldn't bring quality, then he wouldn't bring anyone in at all. That meant only Adam Idah and Nicolas Kuhn arrived.
It was the summer window that suggested the manager's call to the board to be braver in the transfer market had been heeded.
Idah signed permanently for £8.5m, only for Celtic to break their transfer record again by paying £11m for Arne Engels. Auston Trusty cost £6m, Paulo Bernardo eventually arrived from Benfica for £3.4m.
While the free signing of Kasper Schmeichel and the million pounds spent on Luke McCowan were reminders that quality doesn't always have to cost a penny, the willingness to invest more in fewer people has raised the bar and changed the narrative.
Located in 18th place in the table, tied on 12 points with Borussia Dortmund, Bayern Munich, Real Madrid and Juventus, Celtic no longer need to convince others that they are once again a Champions League team worthy of respect.
Having played their cards more shrewdly in recent times, they deserve their place at the high rollers' table.