Jose Mourinho's frustration at Manchester United's failure to sign a new centre-back during the summer transfer window is well-documented, yet perhaps even he did not foresee the scale of difficulty his defenders would have against Brighton.
Sunday's 3-2 loss to Chris Hughton's superbly-drilled side was, in terms of the overall performance, arguably United's worst showing under Mourinho. And, damningly for the manager, two of his most high-profile recruits were at the scene.
Victor Lindelof played well for Sweden at the World Cup but has not looked commanding since arriving at Old Trafford from Benfica last year. Against Brighton, his positioning was very poor, especially when Glenn Murray stole in front of him to flick the game's opening goal past David De Gea.
Yet as much as an off day as he had, Lindelof did not endure as harrowing a match as Eric Bailly. The Ivory Coast International is arguably United's most talented central defender, with speed, technique, passing range and bravery in the challenge.
However, each of his flaws came to the fore against Brighton and, for the first time since his 2016 arrival from Villarreal, he looked like a work in progress. He dived in too soon for several tackles, was caught off balance when he conceded a penalty, and his positioning was generally awry throughout.
There is a strong argument that United should have signed an experienced player to deploy alongside either Bailly or Lindelof, but the club should also have expected better from such signings who cost £30 million.
That is not to say they were alone in playing significantly beneath their best -- Paul Pogba, for one, made more mistakes in 90 minutes than during an entire stellar World Cup campaign with France -- but the mistakes of Bailly and Lindelof were of a costlier magnitude than anyone else.
What should Mourinho do now? Counterintuitively, perhaps the key thing would be to not change too much. For all the criticism of the manager as a conservative coach, he has actually done something quite radical in fielding Andreas Pereira and Fred alongside Pogba in midfield.
That is an entirely new configuration and will need some time to gel, yet it may make sense for one of those players -- probably Pereira -- to make way for Ander Herrera. He and Fred are fine players, but do not offer the same level of match control, while early impressions suggest Fred may be better suited as a less defensive member of a midfield trio. Mourinho might also consider fielding Jesse Lingard ahead of Juan Mata, to offer greater pressure on the ball in the final third.
Otherwise, United could usefully field the same line-up against Tottenham Hotspur next Monday. They will not be short of motivation to redeem themselves and there is something to be said for playing a settled defensive line-up. Bailly and Lindelof are unlikely to combine for another match so catastrophic; to drop them both would adversely affect their confidence.
Maybe Pogba made the most perceptive point about United's loss to Brighton: That it was fundamentally a question of attitude. United, though they lost to the same team at the end of last season, looked unprepared for the intensity of their opponents; surely they are unlikely to underestimate Spurs in the same manner.
If anything positive can be taken from this result, it is the severe wake-up call served to Lindelof and Bailly and the chance it offers both to show the focus and resilience that have made them two of the world's most talented young defenders. If Mourinho keeps the faith, they can find the courage to repay him.