Match ends, Manchester United 0, Southampton 1.
Southampton picked up their first league victory over Manchester United at Old Trafford in 27 years to move up to third in the Premier League.
Louis van Gaal's side failed to record a single shot on target as their 10-match unbeaten league run was ended.
Dusan Tadic scored the only goal of the game when he tapped in calmly from 12 yards after Graziano Pelle's effort had come back off the near post.
The Reds improved after the goal but Juan Mata missed two good chances.
It is the first time United have been beaten at home since their opening day reverse against Swansea and reaffirms Southampton's top-four credentials, as Ronald Koeman's side backed up their home win against Arsenal with another three points.
The visitors had not won at Old Trafford in the top tier since January 1988 - a run stretching back 19 games - and this result was built on a 10th clean sheet in 21 games.
Even after centre-half Toby Alderweireld left the pitch injured in the first half, Southampton remained well-drilled and limited United's array of attacking talent to very few chances.
United's front four, plus wing-backs Luke Shaw and Antonio Valencia, cost the club almost £200m in transfer fees but the best they managed in a poor first half was Angel Di Maria's shot which was dragged past an upright.
Nathaniel Clyne also shot wide for the visitors, while some smart defending from Jose Fonte blocked Robin van Persie's effort.
The game was being played at a sedate pace and only burst into life when Tadic completed a fine move after good work from James Ward-Prowse and Pelle.
United took off former Southampton full-back Luke Shaw and switched Daley Blind to the left, and the Dutchman's dangerous deliveries presented the Reds with two good chances to level.
First, he whipped in a dangerous ball which goalkeeper Fraser Forster failed to deal with and Mata's shot went just wide.
Minutes later, Blind drove a low ball into the box and Mata stabbed over from six yards out.
However Saints held on for arguably their most impressive victory of the season and one which puts them three points clear in the Champions League places.
- 1de Gea
- 16CarrickBooked at 76mins
- 25A Valencia
- 3ShawSubstituted forBlackettat 64'minutes
- 20van PersieBooked at 58minsSubstituted forHerreraat 61'minutes
- 7Di MaríaSubstituted forFellainiat 72'minutes
- 6José Fonte
- 17AlderweireldSubstituted forGardosat 21'minutes
- 21BertrandBooked at 35mins
- 8DavisSubstituted forReedat 80'minutes
- 19PellèBooked at 75mins
- 22EliaSubstituted forTadicat 63'minutesBooked at 70mins
- Phil Dowd
- Shots on Target
Second Half ends, Manchester United 0, Southampton 1.
Corner, Southampton. Conceded by Ander Herrera.
Delay over. They are ready to continue.
Delay in match Dusan Tadic (Southampton) because of an injury.
Attempt missed. Graziano Pellè (Southampton) left footed shot from the left side of the box misses to the right. Assisted by Dusan Tadic.
Offside, Southampton. Fraser Forster tries a through ball, but Graziano Pellè is caught offside.
Foul by Marouane Fellaini (Manchester United).
Jose Fonte (Southampton) wins a free kick in the defensive half.
Corner, Manchester United. Conceded by Jose Fonte.
Attempt blocked. Ander Herrera (Manchester United) header from the centre of the box is blocked. Assisted by Antonio Valencia with a cross.
Attempt missed. Juan Mata (Manchester United) left footed shot from the centre of the box is close, but misses to the right. Assisted by Antonio Valencia with a cross.
Foul by Juan Mata (Manchester United).
Morgan Schneiderlin (Southampton) wins a free kick in the defensive half.
Substitution, Southampton. Harrison Reed replaces Steven Davis.
Attempt missed. Juan Mata (Manchester United) left footed shot from very close range is too high. Assisted by Daley Blind with a cross.
Offside, Southampton. Nathaniel Clyne tries a through ball, but Steven Davis is caught offside.
Attempt missed. Juan Mata (Manchester United) right footed shot from the right side of the box is close, but misses to the left.
Michael Carrick (Manchester United) is shown the yellow card for a bad foul.
Foul by Michael Carrick (Manchester United).