United defended badly for all three goals. Mario Melchiot was left unchallenged to head home the first, while they backed off to allow Jimmy Floyd Hasselbaink to score the second.

They could have done better too for the third which Eidur Gudjohnsen scored from a narrow angle on the left.

Ferguson turned to Roy Keane in United's hour-and-a-half of need and deployed his captain as an emergency centre-half.

This positional change allowed Ferguson to revert to his tried-and-trusted 4-4-2 formation.

Paul Scholes moved back into midfield, while Andy Cole partnered Ruud van Nistelrooy in attack.

But United's back line looked as porous as ever, and Chelsea went past right-back Wes Brown and Laurent Blanc as if they were not there.

After Scholes had been booked in the first minute for a scything challenge on Graeme Le Saux and Carlo Cudicini had pushed away a van Nistelrooy shot, Chelsea capitalised on United's defensive weaknesses to open the scoring.

Six minutes had elapsed when Hasselbaink floated over a corner from the right and Melchiot came steaming in unopposed to head home his first goal of the season from six yards out.

United were a mess, and the woodwork saved them when Le Saux let fly with a volley which beat Fabien Barthez, but not the crossbar.

Chelsea underlined their superiority when they scored a second goal on 64 minutes, which is likely to cause Ferguson even more nightmares.

Juan Veron gave the ball away in his own half, and Gudjohnsen broke up field. As United's ragged defence backed off, the Icelandic international fed Hasselbaink on the right and he drove the ball home across Barthez into the far corner.

Gudjohnsen plunged United deeper into the mire when he scored his eighth goal of the season four minutes from time.