As the final whistle blew on Manchester United’s European campaign, the cast list on the pitch included Jonny Evans, Kobbie Mainoo, Facundo Pellestri and Hannibal Mejbri. One represents the past, another may be the future, two are likely to be footnotes in any account of United. The understudies – in some cases, the unknowns – representing a club who have spent £400m in 18 months, some £1.5bn in 11 years since Sir Alex Ferguson retired were the unwitting indications of how plans went awry. They ended up beaten by Bayern Munich with the kind of line-up likelier to be found in a pre-season friendly.

In different ways, it had gone wrong for their supposed superiors. Marcus Rashford’s Champions League season was curtailed early: United were 2-0 up against FC Copenhagen, looking likely to qualify when his accidental stamp on Elias Jelert brought a sending off then a suspension, before illness ruled him out of the Bayern match. For Casemiro, too, his final contribution was a red card, sent off in the second game against Galatasaray, the victim of one of Andre Onana’s blunders, banned and then injured thereafter. So much for the idea a multiple Champions League winner could have the same effect at Old Trafford. His sidekick in success at Real Madrid, Raphael Varane was an unused substitute when United conceded three goals in Istanbul to take their destiny out of their own hands.

They may have traded their chance of European glory for the supersized pay cheque United offer but, like Rashford, the Real Madrid alumni were supposed to be the cornerstones of a side primed to return to Europe’s top table. They were packed with pedigree but Mason Mount, another Champions League winner, played in two matches; United got points in neither.

Erik ten Hag had signed the goalkeeper who kept five clean sheets to take Internazionale to last season’s final. Onana ends United’s European misadventure with one, secured with his penalty save against Copenhagen. Yet the debit column featured four major mistakes: for Leroy Sane’s opener in Bavaria, setting the tone for the campaign, for Casemiro’s dismissal, for Hakim Ziyech’s two goals in Istanbul. He conceded 15 goals, more than any other Premier League goalkeeper had ever let in during a Champions League group stage. Over a six-game pool stage, it is rare one player has done as much to eliminate his club.

“We gave it away sometimes by individual errors, not one player but more players,” said Ten Hag, seeking to share the blame. Certainly Diogo Dalot was at fault for Wilfried Zaha’s goal for Galatasaray, and perhaps Copenhagen’s equaliser in Denmark, while Sofyan Amrabat’s lamentable attempt to play offside was a reason for Mauro Icardi’s winner for the Turkish champions at Old Trafford.

But the errors were not confined to those on the pitch. Injuries have been a factor in some of the selections that have scarcely made United look a European power, but so have choices. Hannibal was miscast as a Champions League starter against Galatasaray, his haplessness epitomised when he inadvertently blocked a goalbound Mount shot. Varane was benched in Istanbul. Even in the home win against Copenhagen, Amrabat was awful and had to be taken off at half-time. Tactically, United failed to shut the game down when 2-0 up in both Denmark and Turkey.

They nevertheless scored enough goals to go through: 12, as many as Bayern, four more than Inter. They exited the competition while Rasmus Hojlund was its joint top scorer. It could be overlooked because his five goals all came in defeats, because his valedictory outing saw him dominated by Dayot Upamecano and suffer by comparison with Harry Kane. Bruno Fernandes registered two goals and two assists, though his campaign may be remembered for the two free kicks he gave away, which Ziyech took and Onana fumbled.

Hojlund and Fernandes, given the striker’s youth and the captain’s status as the best player at the club, may be more likely than most others to play for United in the Champions League again. But, with United six points off fourth and in an increasingly demoralising season, it is far from certain they will return to it next year.

So some of them may not be back in a red shirt: perhaps not the ageing contingent of Casemiro, Varane, Evans, Harry Maguire and Christian Eriksen; maybe not younger players of questionable calibre like Hannibal and Pellestri; possibly not Ten Hag signings such as Amrabat, Antony and Onana, should there be change at the helm.

For United, European games at Old Trafford in 2023 were bookended by the visits of the aristocracy. Bayern was an anticlimactic end, the victory over Barcelona offering an apparent indication that United were back on the continental stage. Not now. This was definitely their worst continental campaign since 2005-06, perhaps their worst ever. And in the inquest, there is plenty of blame to go around.