Southampton 0 Manchester United 4: When Alex Ferguson and Harry Redknapp were chatting in the Southampton manager's office before kick-off, the subject of the Champions League cropped up. "He thinks Chelsea might win it," Redknapp said later. Evenings like this may heighten Ferguson's frustration at the standing of his Manchester United team, now out of the running for that prize.

It was hard to read too much into events here because a Southampton side missing several regulars were so poor.

But the way United outclassed their opponents, four days after going out of Europe in Milan, suggests that they are in no man's land: too good for almost everyone in the Premiership but short of what is needed in the Champions League and adrift of an exceptionally consistent Chelsea.

For Ferguson that is a familiar feeling. Last season the FA Cup provided his only trophy as United finished 15 points behind the champions, Arsenal, and departed Europe equally early. With the Cup again offering the Scot his only possible silverware, he reflected that defeat had been "unthinkable".

Ferguson got a noticeably positive reception from United fans after a difficult week.

The United manager is upbeat about his squad's outlook in the Champions League, even if he feels the present might belong to Chelsea. "This is the start of a long road towards future European success," Ferguson said. "I think this team will get there because we are already not that far away."

Southampton, though, were miles adrift. Rarely has the gulf between two Premiership clubs been so gaping in favour of an away team this season. Yet in far less demanding circumstances than against Milan, the goals flowed again and the quality of certain individuals team stood out.

Paul Scholes and Roy Keane, before his substitution, exerted an unbreakable hold on central midfield and impressed with the speed and accuracy of their passing. Scholes was once caught in possession, but it was otherwise hard to recall a moment when he did not pick out a team-mate, sometimes with great style. He ended with two goals, Keane with one.

Matt Oakley and Paul Telfer never looked capable of containing them, and their task was made even more difficult by the regularity with which they were outnumbered as United played 4-3-3, with Quinton Fortune starting in a narrow position and Wayne Rooney also dropping infield at times.

United almost always had a spare man, and Southampton, who badly missed the energy and strength of the Cup-tied Nigel Quashie, could not get close enough to disrupt their rhythm. Passes zipped across and through them.

Nor could the defence cope with the effervescent Rooney, quiet against Milan but here combining movement, power, skill and determination. Drifting into areas that troubled Southampton, he had a role in three goals and twice saw Paul Smith push his shots on to woodwork.

All over the pitch United had a greater hunger than Southampton, whose one testing shot came in the ninth minute. If that reflected the resolve of Ferguson's players to salvage something from this season, Rooney's tenacity was perhaps amplified since he is searching for the first medal of his career.

Southampton's ability to bounce back in their relegation fight ought to be helped by the return of Quashie, Jamie Redknapp and Graeme Le Saux at Middlesbrough next weekend. Rory Delap should replace the 18-year-old right-back Martin Cranie, who featured for the youth team last Tuesday and whose inexperience was exposed by United. Antti Niemi will come back in goal instead of Smith. "When everybody's fit I still think we can (stay up)," said Redknapp.

He still must hope matters do not go to the last day, when United visit again. "We'll be back to send you down," mocked their fans, one of whom faces a life ban by his club for throwing a flare into Smith's penalty area after the third goal. It landed a few feet from the goalkeeper. The FA will contact Southampton and the police and expect the perpetrator, if identified, to get a court banning order.

For most of the match Smith's goalmouth had come under more conventional bombardment, Keane finding the net inside 90 seconds via Peter Crouch. Ruud van Nistelrooy compensated for his lack of goals by teeing up Cristiano Ronaldo for the second and Scholes for the fourth, with Scholes slamming in the third in between.

United's league game at home to Chelsea, scheduled for FA Cup semi-final weekend, will now be rearranged.

United's season remains alive but they are in no man's land.