Manchester - Debutant Charlie Austin's late goal earned Southampton a 1-0 victory at Manchester United on Saturday that put the pressure back on beaten manager Louis van Gaal.
Austin joined Southampton for £4m from Queens Park Rangers last week and made a spectacular debut as a substitute at Old Trafford.
The striker, a prolific scorer for QPR, Burnley and Swindon Town, had been on the pitch for only seven minutes when he powered home a header from James Ward-Prowse's 87th-minute free-kick.
His goal handed United a fifth defeat in 10 games, leaving them five points off the top four, and despite a five-match unbeaten run before this, Van Gaal's side have won just three of their last 13 games.
That record, and the bland style of football that has contributed to it, is doing nothing for Van Gaal's job security and while the Dutchman has been unhappy with speculation about his position, it will only intensify after this latest dismal defeat.
United have failed to score at home in seven matches this season and their chances of finishing in the top four to secure Champions League football next season are diminishing fast.
Having gone 17 years without an away win over United, Southampton won at Old Trafford for the second season in a row.
United's first-half showing was as bad as anything they have served up in a dreary campaign, with the home supporters showing their displeasure before the break.
It took just 35 minutes for the first boos and chants of 'Attack!' to be heard after another aimless ball from the back dropped harmlessly into the arms of Fraser Forster.
The Southampton goalkeeper had been a virtual spectator as United's promising start faded away, along with their seemingly fragile confidence.
Looking to score for the fifth successive game for the first time since 2010, Wayne Rooney tried his luck with a couple of efforts, but they never looked likely to bring him a goal.
Wideman Jesse Lingard, whose focus was more on defending than supporting United's attacks, saw a tame shot go wide from a rare foray forward.
Indeed, it was Southampton who had the best chance to take the lead in the first half.
Nine minutes before half-time Dusan Tadic released Sadio Mane with a perfect pass that the forward failed to turn into a serious effort on goal with just David de Gea to beat.
The introduction of Juan Mata at half-time in place of Marouane Fellaini lifted the crowd and United's tempo as they finally started to stretch the Southampton defence.
Mata and Rooney combined to almost find a way through, but the Saints remained dangerous on the break and it took a brave defensive header from Matteo Darmian to prevent Shane Long from reaching Mane's cross.
Darmian was injured in the incident and went off, to be replaced by Paddy McNair.
It was a further source of concern for Van Gaal, who has already indicated his desire to try and sign another full-back after losing Ashley Young, Marcos Rojo, Luke Shaw and Antonio Valencia to injury.
McNair replaced Darmian in what was virtually a five-man United defence, and which was almost undone from successive corners as Long and Victor Wanyama both headed wide.
United did not heed that warning, though, as they continued to look vulnerable from set-pieces and three minutes from the end of normal time they were sunk.
Austin is a penalty-area predator and the 26-year-old cleverly found space to beat De Gea with a perfectly directed header from eight yards out.
De Gea prevented a second goal as he saved from Oriol Romeu, but United could not make the most of that reprieve.
Adnan Januzaj, back as a substitute following his unhappy loan spell at Borussia Dortmund, shot just wide in stoppage time, but there was to be no late equaliser to keep the heat off Van Gaal, as the fans booed their team off the pitch.