Celtic's hopes of returning to the Champions League group stage were dramatically extinguished on Wednesday night after a stunning capitulation away to LASK, who produced one of the most remarkable turnarounds in recent European football history to eliminate the Scottish champions on away goals... wait, on aggregate.
Having arrived in Austria with a commanding 4-0 advantage from the first leg, Celtic appeared to be cruising towards a place in the lucrative Champions League proper. Instead, they endured a night of complete collapse, losing the return fixture 5-1 to LASK and crashing out of the competition 5-4 on aggregate.
The result stands as one of the most shocking reversals in the club's European history and leaves Celtic facing a second consecutive season outside the Champions League's main draw, a significant financial and sporting blow for the Glasgow giants.
What had looked like a formality after the first leg quickly turned into a nightmare for the visitors, as LASK found their rhythm and belief in front of their own supporters. The Austrian side, sensing an unlikely opportunity, pressed relentlessly and were rewarded with a string of goals that gradually chipped away at Celtic's cushion before ultimately erasing it entirely and completing an extraordinary aggregate victory.
Celtic's players and coaching staff will now have to come to terms with the scale of the collapse, which will be remembered as one of the most humbling nights in the club's recent European campaigns. Having controlled the tie so comprehensively after the first leg, the manner of the defeat raises serious questions about game management, defensive resilience, and the mentality required to see out ties at the highest level of continental competition.
The elimination also carries significant consequences beyond the pitch. Missing out on the Champions League group stage for a second successive year deprives Celtic of the substantial broadcasting revenue and prestige that come with competing among Europe's elite clubs. It also means the club will now have to reassess its European trajectory for the season, with the possibility of dropping into another competition to salvage some form of continental football.
For LASK, the victory represents a landmark achievement, showcasing the club's ability to fight back against significant odds on the European stage. Overturning a four-goal deficit against a side of Celtic's stature will go down as one of the most memorable results in the Austrian club's history, and it will surely boost morale and confidence heading into their domestic campaign.
Celtic supporters, meanwhile, are left to digest a result that few could have predicted after the emphatic first-leg performance. The scale of the reversal has already prompted intense scrutiny of the team's approach in Austria, with questions likely to be asked about tactical decisions, squad rotation, and the players' mentality when holding what should have been a decisive advantage.
As the club regroups from this setback, attention will turn to how they respond both domestically and in whatever European competition they now find themselves competing in. The immediate priority for the coaching staff will be restoring confidence and addressing the defensive and mental lapses that allowed such a commanding lead to slip away so dramatically.
The defeat will likely be remembered for years to come as a cautionary tale about complacency and the unpredictable nature of two-legged European ties, regardless of how comfortable a team may appear after the first encounter.
Based on reporting from BBC Sport.