Charlie Austin's debut Southampton goal piles pressure on Louis van Gaal
Charlie Austin scored the winner with his first touch in a Southampton shirt to pile the pressure on beleaguered Manchester United manager Louis van Gaal.
United supporters once again vented their anger towards Van Gaal after watching their team put on yet another dull, uninspiring performance at Old Trafford.
Boos rang out around Old Trafford at half-time and following the final whistle as Saints recorded only their second win at United's home since 1988, but also their second in 13 months.
There was no doubting who the home supporters blamed for this latest insipid display. Van Gaal was jeered at as he walked down the tunnel. The message was clear - he is no longer wanted by some of them.
United's fans had every right to feel let down by the United manager.
This was dour stuff from United, possibly the worst performance of what has been a forgettable season. And they are now five points behind fourth-placed Tottenham with 15 matches to go.
United too often shifted the ball sideways and backwards, which caused groans from the home supporters. And when Austin rose unmarked to power in James Ward-Prowse's free-kick in the 87th minute, it came as no surprise.
United offered next to nothing in front of goal. Fraser Forster had one save to make all match.
Van Gaal claimed in his programme notes that United had started 2016 "well", but the home fans who were put through yet another dreadful 45 minutes must have disagreed.
Yes, results had improved recently, but the style of play has not. United were often ponderous in possession and seemed too nervous to pass forward.
Daley Blind provided Forster with his only test of the opening 45 minutes, but the England goalkeeper had little trouble collecting the Dutchman's long-range shot.
Wayne Rooney dragged a shot wide and Anthony Martial tried to chase a short backpass from Virgil van Dijk, but otherwise there was little optimism from the home supporters.
Those who left their seats for their half-time refreshments just after the half hour mark missed the best chance of the half. It went to Southampton, who should have taken the lead when Dusan Tadic played a one-two with Sadio Mane but the striker's touch let him down and David de Gea collected.
Boos rang out when United pumped the ball forward twice in quick succession and more jeers came when the half-time whistle sounded.
Cheers greeted the announcement that the blundering Marouane Fellaini, who had earlier caught Victor Wanyama with his forearm while jumping, was to be replaced by Juan Mata.
The Spaniard injected purpose and energy into United's attacks. Mata laid the ball off to Martial inside the box, but Van Dijk put in a well-timed interception to deny the Frenchman.
Saints rose to the challenge, launching an assault on the United defence around the hour. Wanyama and Long went close with headers from inside the box.
Van Gaal was forced into an unwanted substitution when Matteo Darmian, the club's only fit senior full-back, was replaced by Paddy McNair after being caught in the ribs by Long while jumping for the ball.
Austin came on for his Saints debut with 12 minutes to go. His strike partner Long wasted a good chance by heading over James Ward-Prowse's cross.
Austin did not pass on his opportunity, however. The £4million signing lost his marker and powered in Ward-Prowse's free-kick before Van Gaal walked down the touchline to boos and whistles from the home fans.
TWEET OF THE MATCH
"7 wins in 22 for #mufc now all comps. 5 PL wins in 16. Every forward step followed by two backwards. How much longer can LvG cling on?" - Sport Journalist Adam Crafton (@AdamCrafton_) questions how long Louis van Gaal can keep his job at Old Trafford.
David de Gea: 6 (out of 10)
Cameron Borthwick-Jackson: 5
Chris Smalling: 6
Daley Blind: 5
Matteo Darmian: 6
Morgan Schneiderlin: 5
Marouane Fellaini: 5
Jesse Lingard: 6
Ander Herrera: 6
Anthony Martial: 5
Wayne Rooney: 5
Juan Mata: 6
Paddy McNair: 5
Adnan Januzaj: 5
Fraser Forster: 6
Cedric Soares: 6
Jose Fonte: 7
Virgil van Dijk: 7
Ryan Bertrand: 7
Matt Targett: 6
Jordy Clasie: 7
Dusan Tadic: 6
Victor Wanyama: 7
Sadio Mane: 7
Shane Long: 6
Oriol Romeu: 6
James Ward-Prowse: 6
Charlie Austin: 7
Ryan Bertrand. The England international - who is currently being linked with United - was one of several Southampton defenders to put in a solid shift. Jose Fonte and Virgil van Dijk also impressed.
MOMENT OF THE MATCH
Charlie Austin's goal. Eight minutes after coming off the bench, Southampton's new striker marked his debut with the first thing even approaching clinical finishing the game had seen as he nodded in fellow substitute James Ward-Prowse's free-kick.
VIEW FROM THE BENCH
After a more encouraging performance attack-wise against Newcastle and good result at Liverpool, Louis van Gaal was looking for a combination of the two from his team here. But he saw them deliver neither, United producing another home display devoid of creative spark and condemned to defeat by Austin's late header.
Van Gaal's counterpart and fellow Dutchman Ronald Koeman will be delighted with a sturdy, patient effort from Southampton that was rewarded with all three points after the new frontman was thrown on.
MOAN OF THE MATCH
There had been signs of late that things were starting to pick up for Van Gaal's side, but this was another performance to leave United fans wondering what direction their club is heading in. The Red Devils seem incapable of building any momentum at the moment and the players appear to be hampered by nerves at their own stadium.
Derby County v Manchester United, FA Cup fourth round, Friday 29 January.
Arsenal v Southampton, Barclays Premier League, Tuesday 2 February