Keane had been called upon as early as the interval when Ferguson brought him on after a dismal first-half showing by United. And it was the Republic of Ireland midfield who put United on the road to yet another three points when he broke the deadlock with a vital strike 11 minutes from time. That goal broke Southampton's hearts and Dwight Yorke added a second in the 83rd minute before substitute Matt Le Tissier pulled one back in stoppage time for the plucky, but unlucky visitors.

United had insisted they would not be distracted by their midweek date with the Italians, but from the first whistle it was clear their minds were elsewhere. They did not look like the Premiership leaders who had won nine of their 10 games in 1999. Instead it was relegation-threatened Saints who were the brighter. Birthday boy James Beattie, who was 21 today, headed wide early on from Egil Ostenstad's cross which was just a touch too high.

United briefly roused themselves from their sluggish start in the 13th minute when the impressive Ken Monkou headed away a dangerous Ryan Giggs cross for a corner. From the setpiece, Patrick Colleter cleared a Yorke header off the line from David Beckham's corner. But in the main it was Southampton who were playing the better football on United's patched-up pitch and Chris Marsden forced a decent save from Peter Schmeichel from 25 yards out.

Ferguson livened up the rather dull proceedings when he came down from his perch on the sidelines to barrack the assistant referee over a baffling offside decision given against Yorke. Back on the pitch, Ostenstad knew he should have done better when the United defence opened up in front of him, but he shot weakly at Schmeichel.

United picked up the pace before the interval and Saints skipper Jason Dodd denied Giggs a 43rd-minute opener. Beckham escaped down the right and crossed to the back post only for Dodd to stop the Welshman's header on the line.

United slowly improved in the second half and Yorke had a header blocked before Giggs was left cursing himself on 59 minutes when he squandered a terrific chance.

Ole Gunnar Solskjaer centred from the left for Giggs to scoop the ball carelessly wide of the target with only Jones to beat. With a quarter of the game remaining Southampton brought on Le Tissier, who had started on the bench following his recovery from calf and hamstring problems. United also made a change and Cole came on for Solskjaer to receive the biggest cheer of the afternoon so far.

Le Tissier quickly made an impact and within seven minutes of coming on Beattie headed his corner against the bar. To compound Saints' woe Keane gave United the lead five minutes later. Henning Berg nodded down Beckham's corner and Yorke set up Keane to score with a deflection for his fourth goal of the season.

Worse was to follow for Southampton and in the 83rd minute Beckham found Yorke unmarked on the left in acres of space and he rounded Jones before slotting home his 22nd goal of the campaign.

There was still time for Beattie to hit the woodwork again when it would have been easier to score after Schmeichel had saved from Le Tissier. Le Tissier restored some pride for Saints when he scored in stoppage time, but it will be of little consolation to Dave Jones' side who on another day might easily have won.