The one, tiny consolation for Luiz Felipe Scolari was that Roman Abramovich stayed away. Chelsea’s most humiliating defeat since Claudio Ranieri lost the plot in Monaco five years ago was witnessed by many of the great and good of world football, from Diego Maradona to Fabio Capello, but not the man who will pick up the bill for this performance. The Chelsea manager must also hope that the satellite on the Russian owner’s yacht, where he had been enjoying his new year holiday, malfunctioned as badly as his team.

Chelsea have suffered the occasional bad defeat since Abramovich bought the club – with a top-flight thrashing away to Middlesbrough and FA Cup semi-final defeat by Liverpool springing immediately to mind – but never in such a comprehensive fashion against a leading rival. To make matters worse, this horror show was witnessed by the man responsible for the club’s greatest glories, José Mourinho, whose concerns about Manchester United’s impressive form before next month’s Champions League tie with Inter Milan will be offset by the stark evidence of Chelsea’s decline in his absence.

The warning signs have been there for several weeks, with poor performances compounded by a series of complaints from the dressing-room, but the manner of this defeat was still shocking. To his credit, Scolari was willing to take the blame, reasoning that his decision to change the shape of his side to push for an equaliser created the space that United exploited so ruthlessly, but this essential truth should not disguise the woeful second-half effort of many of his players. If the performance-related contracts Chelsea are considering had already been in place then Didier Drogba, Michael Ballack, Deco and Joe Cole would have received nothing yesterday.

Scolari has little time to turn things around before an FA Cup third-round replay against Southend United on Wednesday that could cause even greater embarrassment, and when he sits down to watch this X-rated video he may not know where to start. A priority must be to sort out the shambolic defending that made Mourinho wince in horror, as even Coca-Cola League One sides can hurt them from set-pieces at the moment, as Southend demonstrated at Stamford Bridge nine days ago.

It is astonishing that six of the past seven goals Chelsea have conceded have come from set-pieces and even the odd one out – Wayne Rooney’s goal yesterday – was the result of a cross by Patrice Evra that travelled the full width of the visiting team’s penalty area. Many of the problems can be attributed to individual errors, with John Terry losing Nemanja Vidic for United’s first goal and Dimitar Berbatov drifting between the Chelsea captain and Ballack for the third, though the Chelsea manager must take responsibility for asking Franco Di Santo, 19, to mark the Bulgaria striker.

Turning the mass of individual talent into a coherent midfield unit may take rather longer, particularly since Deco and Ballack appear uninterested. The Portugal midfield player was given a rare opportunity to operate centrally – with Frank Lampard briefly shoved out wide – and was deservedly replaced at half-time by Nicolas Anelka.

Given his tally of 16 goals this season – where would Chelsea be without them? – Anelka can feel aggrieved at being overlooked from the start, especially since Drogba produced a performance more fitting to a pantomime than the Theatre of Dreams. The Ivory Coast striker was at his self-indulgent worst, repeatedly going to ground, producing air shots and intensifying a pathetic limp as the scale of the defeat became apparent. To make matters worse, Chelsea also lost their discipline, picking up five yellow cards as they struggled to adapt to an unfamiliar plight.

In the past Chelsea would have been certain to bounce back with a long unbeaten run, but such a defiant response can no longer be taken for granted because there are even question marks hanging over their previously peerless team spirit. Drogba, Ballack and Deco bear the pained expressions of unhappy men who would rather be somewhere else, while their minimal contributions have upset many of their teammates.

The board’s response will also be fascinating because the wholesale refurbishment of the squad that is clearly needed is likely to have to wait until the summer. In the past Chelsea would simply have thrown money at the problem, but in the prevailing economic circumstances, that is no longer possible, unless Abramovich has a change of tack by selling one of his yachts.