Celtic have spent the last couple of years making Champions League qualification look like a problem they simply cannot solve. But even by their recent standards, this was a collapse of remarkable proportions.
Four goals ahead with less than an hour still to play across the tie, Celtic somehow found themselves on the wrong end of a 5-4 aggregate defeat to LASK. A place in the league phase was theirs to lose - and they lost it spectacularly, with individual mistakes, questionable decisions and a team that appeared to run out of answers when the pressure mounted.
The fallout will inevitably focus on Martin O'Neill, who took responsibility for the defeat afterwards. But this feels like a much bigger failure than one manager or one night. It raises questions about the squad Celtic have assembled, the decisions made in the transfer market and whether the club were truly prepared for their biggest test of the season.
So, let's break down Celtic's current situation.
O'Neill took full responsibility. But the truth is they are all to blame. Should the Celtic players be blowing a four-goal lead with less than an hour to play? No.
Did individual errors and complacency cost them on the night? Yes.
Did O'Neill make the right subs? Probably not - the team was severely weakened with every change and then, similar to Thomas Tuchel's England against Argentina, they were left with no attacking options when the inevitable happened.
But were Celtic fully prepared for this qualifier, compared to last season? They were certainly more prepared.
The signings of Kasper Hogh, Camilo Duran, Mika Baur and Haissem Hassan cost around £32m. They appear to have improved the squad, and the starting line-up is undoubtedly stronger. But there were still gaping holes that needed filling.
Celtic knew Arne Engels was likely to leave, but weren't able to replace him in time for LASK. They knew Kieran Tierney needed cover, but they still haven't brought in a back-up left-back. Alistair Johnston's injury was a late blow, but they perhaps should've been ready with a replacement as he was close to leaving before his injury. So, while good signings have been made, they were not fully prepared for this tie.
For a Celtic team to finish a Champions League tie with likes of Dane Murray, Liam Scales, Anthony Ralston and Luke McCowan on the field suggests how threadbare they still are.
Also, it could be argued that postponing their Scottish Premiership match with St Johnstone at the weekend was a mistake, given how dead on their feet the team looked in the second half and in extra time in Austria. Some of them could've done with the extra minutes at the weekend.
Missing out on the Champions League could have huge consequences for Celtic in the last week of the transfer window. Celtic would've been guaranteed another £40m from Europe's premier competition. But they know the reality is much more than that, having made around £75m from their Champions League exploits two seasons ago.
Had they made it there last night, they were expecting to spend in excess of £20m this week on a number of players, including Torino's Gvidas Gineitis and Slovan Liberec's Ermin Mahmic. It remains to be seen whether those deals can still be done, but Gineitis certainly seems unlikely given that he would cost around £10m.
When there's Champions League football on offer, there's no doubt you can operate in a different market. The finances that come with it are huge, but also the lure it has on players is a big draw and sometimes a deciding factor on whether they will join a club in the Scottish league. Even up to yesterday afternoon [Tuesday], it's understood Celtic were being offered some top European talent, via intermediaries, who were seeking to play for a Champions League club this season. That's gone now.
Celtic are in the market for a couple of central midfielders, a goalkeeper, left-back, right-back and possibly even a left winger, before next Thursday's deadline. It's a lot of work to do in a week, with a threadbare team of people doing it but the show must go on to fill the gaps in the squad.
While money is likely to be spent on a midfielder and goalkeeper, some of the other positions may now come from loans. The Celtic hierarchy, recruitment team, O'Neill and Maloney are expected to meet this week to discuss the plan of action for the last week of the window.
Despite the glorious ending, last season was a bit of a nightmare for everyone involved in Celtic. No Champions League and poor transfer windows led to mass protests against the board, campaigns to boycott merchandise, a managerial resignation, ultras bans, a managerial sacking and a disjointed team that was carried over the line to a double by O'Neill.
There is only one way to avoid a repeat of last season - and that is for the board to go all out in the transfer market to build a squad that is capable of winning this season's Europa League. Whether the board have the same appetite to do that is another issue. Is it worth them spending big for the Europa League, when financial rewards aren't the same? The fans will certainly think so - and O'Neill might be the man to help give the hierarchy a nudge to help him, not just compete but be a force in the competition.
The fans are also hoping to see a considerable restructure at the club. Celtic still have board members involved in transfer negotiations and football operations. They got rid of their head of football Paul Tisdale in January and still haven't replaced him. There is still no head of recruitment, and they're still a number of first-team analysts short compared with the Brendan Rodgers era.
Celtic's hierarchy had seemed to be patching things up with the fans with their signings and a good domestic start to the season. Yesterday in Linz, chairman Brian Wilson sat and drank with the fans in the afternoon. A lot more patching up is required now.
If Celtic win the league this season, the task of reaching next season's Champions League is even harder. They will enter at the second qualifying round, meaning they will need to negotiate three ties and six matches to get into the league phase of the competition.
This was the last chance for a while that they just had a play-off to win, and it resulted in the sixth consecutive failure they've had in the qualifiers for this competition.
Celtic see themselves as a Champions League club - in stature and size they are. But it could be a while before their team plays in the tournament again.
One direct way into the tournament is by winning the Europa League…
