The net result was a win and the lead at the top of the premiership stretched to 7 points.
United for large parts of this game were constantly under the cosh and Southampton high tempo approach clearly rattled United into mistakes and in the end there was relief around Old Trafford as the final whistle was blown.
United again started the game with a 4-2-4 formation with Kagawa and Welbeck providing the width for Van Persie and Rooney.
The game got of to an awful start for United when Carrick played back a bouncing ball to De Gea and although his effort was not the best Southampton found themselves a goal up. Michael Carrick owed up to his mistake to detract the critics who seem to have it in for De Gea these days. My view that De Gea did the right make himself big and not touch the player as there was the prospect of a penalty and a red card.
United in shock decided rather than think about that early blip they went on the attack and a cute ball from Kagawa found Rooney who clean on goal guided it past Boruc. United's recovery was completed half way through the half when Rafael replacement Phil Jones made a good run down the wing but was fouled. The resulting free kick saw RVP pick out the aerial threat of Evra who headed across the goal and left Rooney with a tap in from a yard.
In between that Kagawa was unlucky with hitting the post and Welbeck posing several threats with direct runs.
The half ended with Carrick and Anderson dominating the midfield but the second half saw United face a more sterner test.
Southampton were a lot more direct and Puncheon and Lambert were a constant thorn in the United side. Vidic was excelling in the physical battle but Smalling was making a number of errors and was subbed to be replaced by the veteran Rio Ferdinand. The defence looked a lot stronger for the change.
Southampton had a few efforts with a Ricky Lambert free kick well saved by De Gea and Vidic putting in a vital block on a Lambert shot that looked goal bound.
United had few chances and a RVP header was well saved by Boruc and then moments later had a goal disallowed which would have made the last 10 minutes a bit calmer.
United survived and looked a bit more solid when Rafael and Nani came on and Jones being pushed into a more central midfield area.
In the end United got the win and from my point of view Southampton put up one of the best away displays at Old Trafford this season.
Man of the match only one contender and that was the skipper Vidic, he had a difficult night and coped with the aerial and physical threat.
Next up for United is a Saturday night visit to Craven Cottage to play Fulham.