No single reason underlies the current decline of Manchester United , unless it be the immutable law governing the fall of empires. One person whose fault it is definitely not is Paul Durkin, the referee of Saturday's match at Old Trafford, blamed afterwards by Sir Alex Ferguson for his consistent failure to give penalties to the home side.

Ferguson already restricts his post-match remarks to his club's own television station. If his pathetic condemnation of Durkin is the best he can come up with to explain United's fall to ninth place in this morning's Premiership table, he would be doing everyone a favour by expanding his boycott to include MUTV.

Durkin handed out eight yellow cards, five of them to players in red shirts, but the only significant blot on his performance was a failure to spot the elbow which Roy Keane applied to Joe Cole's face in the United penalty area in the 85th minute. A gesture with its origin in frustration rather than malice, it was nonetheless worthy of a red card along with a penalty kick that might have doubled the margin of West Ham's victory.

The United manager's unbecoming but typical petulance failed to disguise his own culpability for his team's sixth league defeat of the season, and their fifth in the last seven matches. Given an injury list including Ryan Giggs, Laurent Blanc, Wes Brown, David May, Ronny Johnsen and Denis Irwin, his decision to award a weekend off to Juan Sebastian Veron and Ruud van Nistelrooy, while also keeping David Beckham out of the starting line-up, smacked of judgment gone seriously awry.

His refusal to send out his strongest team leaves Ferguson facing a charge of taking the opposition too lightly, one of sport's cardinal sins. As with certain other decisions this season, starting with the sale of Jaap Stam, peripheral considerations seemed to have obscured his view of the immediate task.

Might he be piqued, for example, that Beckham, one of his "fledglings", is currently getting better notices for his performances under another manager? Or could he be wanting to prove that he can send out a side stripped of his expensive summer signings and still prevail in domestic competition?

Perhaps West Ham are not the Premiership's most intimidating opponents, yet this is a time when United need a run of victories to re-establish the foundation of self-confidence that would allow them to mount a realistic defence of their title. On Saturday, however, their manager paid the price for apparently sharing in the general delusion that a midweek victory over Boavista in the Champions League had reinfused his players with their familiar virtues.

Glenn Roeder, West Ham's modest manager, prepared for his first non-playing visit to Old Trafford by shuffling his midfield. He switched Trevor Sinclair to the left to restrict the activities of, as he imagined, Veron or Beckham, while posting Don Hutchison to the right, safely out of range of the equally combustible Keane, and pairing Cole and Michael Carrick in the middle. Roeder was shocked when he saw United's team-sheet, but elected to maintain the formation and saw his decision pay off.

Cole and Carrick, a pair of 20-year-olds more noted for artistry than muscle, stood up well to the challenge of Keane and Nicky Butt, as did the 19-year-old Jermain Defoe, who looked composed and lively throughout. Even when United attempted to pour forward in the final quarter of the match, motivated by the visible anger of Keane and Beckham, West Ham were never overrun. And, when the moment came, their young Englishmen were ready to make the vital incision.

In the 64th minute Carrick fed Hutchison, who pushed the ball up to Defoe. Two touches saw the ball transferred to Paolo di Canio and quickly on to Cole, who turned and accelerated away from Butt, evaded Paul Scholes, drew Mikael Silvestre, and released the ball at the ideal moment to give Sebastien Schemmel room and time to choose the target and trajectory of his cross. The right-back opted to clip the ball low to Di Canio, who swivelled inside the area and aimed a chip to the far post, where Defoe rose above Phil Neville to head past Fabien Barthez.

It was a lovely goal, and a credit to all the participants, but it was made possible by Cole's instinct and accuracy and, most of all, by his willingness to take opponents out of the game by carrying the ball past them. This was once Paul Gascoigne's greatest gift, and in Joe Cole it appears to be packaged without a similar risk of self-inflicted damage. It may be too early in his career for him to book a place in England's starting line-up in time for the World Cup finals, but Sven-Goran Eriksson may look at such displays and conclude that it is worth having such a talent on the bench in Japan, ready to break a stalemate.

Scholes, who occupies the England shirt that Cole might one day inherit, was the most consistently dangerous of United's attackers, but found David James equal to a couple of fierce drives, while two of his glancing headers flew wide of the far post. The West Ham goalkeeper was another man who advanced his international ambitions with a series of convincing blocks, punches and fingertip saves.

James's need to demonstrate such agility and authority was all the confirmation anyone could have needed that United were trying their best to pick up where they had left off against Boavista, just as Ferguson could reasonably claim to have sent out a side full of experienced players of proven quality. But the damage seems to be occurring deep within the subconscious mind, at those levels where a manager is thinking too much about his own reputation while his players, accustomed to the secure belief that their destiny is in his hands, cannot help but be wondering with whom their future lies.