COPENHAGEN, Denmark -- Only Erik ten Hag's Manchester United could win a game twice and still lose. When the full story of their wild 2023-24 season is told, there won't be a more inexplicable chapter than the one that describes their Champions League meltdown in Copenhagen on Wednesday.

A prematch tifo unfurled by the home supporters warned United that the Parken Stadium was "Your Theatre of Nightmares," and it couldn't have been more prescient.

Coasting at 2-0 after 30 minutes and then having made it 3-2 to regain the lead on 69 minutes, despite being reduced to 10 players following the first-half dismissal of Marcus Rashford, United threw victory away against FC Copenhagen with shambolic defending in the closing stages that led to the home side scoring twice in the final seven minutes to win 4-3 and send United to the bottom of Group A with two games to play.

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And just to add to the sense of farce surrounding United's misery, the Parken Stadium rang out to chants of "Roony, Roony" at the end. Not as a reminder of United's former great, Wayne Rooney, but in tribute to 17-year-old forward Roony Bardghji, who scored Copenhagen's 88th-minute winner.

"This was our weakest performance in the group so far," Copenhagen coach Jacob Neestrup said. "But we deserve this win for our performances in the other three games."

To be fair to United, their ninth defeat in 17 games in all competitions was not all down to the shortcomings of Ten Hag and his players, with a VAR intervention resulting in a red card for Rashford before Harry Maguire conceded a penalty with a harsh handball decision that sent United veering off course after Rasmus Hojlund scored twice against his hometown team.

But for Rashford's 42nd-minute dismissal for catching Elias Jelert above the shin with the sole of his boot -- a foul that was missed by referee Donatas Rumsas before being flagged by VAR -- United looked on course for an easy victory following their best performance of the season.

Yet the fragility of Ten Hag's team, something that has been evident throughout the season when it faces adversity, resurfaced as soon as Rashford walked down the tunnel, with United's lead wiped out by half-time as Copenhagen scored through Mohamed Elyounoussi and then a Diogo Gonçalves penalty.

The second half, then, was clearly a test of United's resolve. Could they finally shake off their inconsistencies and display the fighting spirit to earn a draw or even a win?

Initially, the answer was yes. Ten Hag replaced Christian Eriksen with Sofyan Amrabat at half-time in an effort to add a more defensive element to his midfield, and United took the sting out of the game and frustrated the home side, despite having a one-man disadvantage.

And when United were awarded a 66th-minute penalty following a handball by Lukas Lerager -- this time VAR found in United's favour -- a remarkable, backs-to-the-wall victory suddenly presented itself.

Bruno Fernandes scored from the penalty spot to put United 3-2 ahead and leave the visitors with just over 20 minutes to hold firm and see the game out for a crucial win, but also a victory that would act as a much-needed turning point for what is quickly becoming a dire season.

But this is Manchester United we are talking about. Not the great, multi-Champions League-winning team of the past, but the modern-day version that has come to typify weakness, chaos and how not to play at the highest level, or any level.

United have shown an ability to chase lost causes this season, scoring late winners against Brentford, Sheffield United and Fulham, but when it comes to holding on to a winning position, they are clueless.

Even with 10 players, most top teams can find a way to defuse a game and run down the clock when the pressure is on, but this United team only crumbles. With less than 10 minutes to play, United invited Copenhagen forward and allowed the Danish champions to camp outside the penalty area. Having scored twice at Old Trafford, Copenhagen already knew that United had plenty of defensive shortcomings and they came to the fore again.

Diogo Dalot was at fault for Copenhagen's third goal when he failed to spot danger and then stop it, when Lerager outfoxed him at the far post to score from close range. Seven days ago, Dalot was similarly careless when allowing Miguel Almirón to score for Newcastle United in United's 3-0 Carabao Cup defeat.

And the Portugal international was also culpable for Bardghji's winner -- a stunning left-foot strike -- when he turned his back on the teenager's shot rather than throw himself at it. United's failure to clear the ball initially was the spark for the goal, but Dalot should have done much better.

"The squad is resilient," Ten Hag argued after the game. "The whole season, so many decisions are against us, but every time, there is spirit and fight. We will keep going and it will turn in our favour.

"Football is a game of mistakes. We didn't do everything right, even with 10 men, we dictated the game. We didn't do everything, but we did many things right."

United are still alive in Group A, but only just, and they will need to show incredible spirit and confidence to beat Galatasaray in what will be a hostile atmosphere in Istanbul.

Despite Ten Hag's comments about "spirit," the reality is that his players are found wanting when it truly matters, and there is no hiding place in the Champions League.