FA CUP/Manchester Utd 4 Arsenal 0:Talent has always set Wayne Rooney apart but it has never been clear whether he should also stand alone in a football team.

He thrived as a lone striker in this drubbing of Arsenal, and here there was no cause to ask if he might not tap even more of his talent when handed complete licence. Alex Ferguson has even spoken, of late, about the need for Rooney to stay up front and reap more goals.

That requirement, though, may reflect a manager putting the interests of the team above those of the individual. With Louis Saha so often injured, United barely have an orthodox attacker at their disposal unless Rooney assumes those duties. The situation is little different for England, where he was used as the spearhead in the win over Switzerland at Wembley.

Rooney persevered laudably that night, but the new manager, Fabio Capello, could not have concluded that the 22-year-old is the very man for the job. The Italian must be conscious of the havoc the player has sometimes caused when roaming freely to display his full repertoire.

Arsene Wenger doubts the benefit of asking Rooney to suppress his instincts. "He's a guy who likes to get the ball and he likes to be busy," said the Arsenal manager. "I don't see him in the long term being a lone striker."

Wenger envisages Rooney having a partner in the England side. "I would put him up front, but maybe with somebody," he said.

The player spoke of the benefit in this FA Cup tie of energetic back-up from midfield. Rooney probably does not do subtext, but listeners could not help but reflect that Nani (21), Anderson (19), and Darren Fletcher, comparatively grizzled at 24, all started the match while Ryan Giggs had the evening off and his fellow veteran Paul Scholes came on purely for a little exercise late in the game.

Ferguson has those old heads in mind for the Champions League match in Lyon. "Ryan will play on Wednesday along with Paul," he said. "Our experienced players will be very important to us."

Against Arsenal, on the other hand, the priority was to put on an intimidating show of vitality. The visitors, with so many injuries, were unsure how committed they wanted to be to the FA Cup and ambivalence turned swiftly to capitulation.

Rooney's commitment contrasted with the diffidence and incompetence of Arsenal. "He was sharp, he was mobile, he was quick, he was aggressive, he was even good in the air," said Wenger. "I think he was just amazing."

Such was Arsenal's plight that neither the striker nor the commanding Anderson may have been United's leading performer. Fletcher, making only his seventh start of the season, acted like a person taking out his frustrations. He was tireless, sharp and dangerous enough to score twice, his first goals for a year.

But the excellence of the Scot and his team-mates was accentuated by the disgraceful showing of the visitors.

With a five-point lead in the Premier League, they had less to prove than United, who came into this fixture after a defeat by Manchester City, but the diffidence was unprofessional. Hapless fringe players were abandoned by key figures such as William Gallas, Kole Toure and Cesc Fabregas, who all made a miserable contribution.

Emmanuel Eboue was sent off for a high challenge on Patrice Evra in the 49th minute and Gallas deserved to be dismissed later for a kick at Nani that went unseen by the referee, Alan Wiley.

Unable to take a grip of themselves, Arsenal definitely could not keep a hold of United, whose opener arrived after 16 minutes. Following a Nani corner Anderson helped the ball into the goalmouth and Rooney jumped to glance it beyond Jens Lehmann.

Nani then persecuted Justin Hoyte before crossing for Fletcher to head home with the aid of a deflection. The Portuguese himself struck eight minutes before the interval. Michael Carrick's technique was wonderful as his pass cleared Gallas and dropped for Nani to fire into the net.

The scorer would go on to mock Arsenal with his trickery and, while both managers criticised him for grandstanding, it is also true that visitors so lacking in commitment invited derision.

Before the end Fletcher had scored with a further header from Nani's service.

There should have been a greater rout and Rooney ought to have helped himself to at least a hat-trick.

The visiting supporters sang that they would be coming back to win the league. It is just about feasible, but United will now believe the encounter in April can be the day they overhaul Arsenal.

- Guardian Service