Manchester United's late-season dip has come as a surprise given their strong start to life under Ole Gunnar Solskjaer, but Sunday's 4-0 defeat to Everton proved that their problems run deep.
Two goals in each half from the Toffees saw the home side blow United away at Goodison Park, as strikes from Richarlison, Gylfi Sigurdsson, Lucas Digne and Theo Walcott put the Red Devils to the sword and sent Solskjaer back to the drawing board.
A Manchester derby on Wednesday and a crucial clash with top four rivals Chelsea lie in wait for United in the next week, and they can ill-afford a similar performance in those games to that which saw them torn apart on Merseyside.
The writing was surely on the wall when Jose Mourinho, one of the most notoriously demanding and defence-savvy coaches in Europe in recent times, struggled to impose defensive structure and stability at Old Trafford.
In the latter stages of his spell in charge of the Red Devils, the Portuguese managed to push Victor Lindelof to perform with greater discipline and resolve but, in truth, the Swede's improvements were the only real successful mark of Mourinho's tenure in defensive terms.
With the likes of Chris Smalling, Phil Jones and Eric Bailly failing to convince on a consistent basis, United have largely been left to bounce between insufficient options in their defensive ranks with players who simply are not good enough to match the ambitions of such a club.
Gone are the days of Rio Ferdinand and Nemanja Vidic's stout rear-guard displays, which set the benchmark and provided the backbone for the later successes of Sir Alex Ferguson's reign at Old Trafford.
United have invested heavily in their squad in recent years, but a fundamental lack of clear direction and incohesive business from above the manager's head has cost them dearly.
Mourinho yearned for a big-money signing of the likes of Harry Maguire or Kalidou Koulibaly towards the end of his tenure, but Ed Woodward and co failed to provide their coach with the necessary tools to lead the club forward.
The Portuguese attempted to bang the drum and wear his heart, and the club's crest, on his sleeve, but was ultimately made the scapegoat as Paul Pogba and co turned on their boss and brought an end to his time in charge.
Solskjaer emerged as the saviour in succeeding Mourinho, allowing the Portuguese to continue to take the blame for United's shortcomings this term as the Norwegian brought the feel-good factor back to Old Trafford.
However, with the season drawing to a close and United's campaign spiralling back to square one, Solskjaer is quickly realising that it was never going to be that easy.
The problems run far deeper, and the Red Devils legend has a huge job on his hands now that the honeymoon period is well and truly over.