Wayne Rooney scored twice as Manchester United opened up a seven-point gap at the top of the Premier League with a comeback victory over Southampton.
Rooney's first-half double put United in control after calamitous defending had led to Jay Rodriguez's third-minute opener for the visitors.
Although the hosts threatened to overrun the Saints before the break, Mauricio Pochettino's side recovered well in the second half, pressing their hosts from the front.
Rickie Lambert could even have equalised as his accurate shooting twice tested David de Gea, although Robin van Persie was also denied by Artur Boruc and had another effort ruled out for offside.
An open and intriguing contest, this was another example of United being saved by their attack and, while they ultimately took advantage of neighbours Manchester City's failure to win at QPR on Tuesday, there will again be questions about their defending, particularly with Real Madrid visiting soon in the Champions League.
Defeat for Southampton ended a six-game unbeaten run, although there were signs of a tactical adjustment to the team from Argentine coach Pochettino, in his second game since replacing Nigel Adkins.
The 40-year-old was certainly true to his pre-match word in going for a win at a venue where Saints have not succeeded in 25 years.
Having earned a draw and a clean sheet in his first game against Everton, Pochettino's start to Premier League life looked even rosier within three minutes as Rodriguez capitalised on Michael Carrick's poor backpass and nipped in ahead of the stranded De Gea to put the Saints in front.
It was a shocking goal to concede and the 12th Premier League game in which United have gone behind this season.
"Southampton worked and worked, they played really well but it's 12 games unbeaten for Manchester United. And most importantly in the numbers game, the gap over Manchester City at the top is back to seven big points."
But, as on the eight other occasions when they have turned a deficit into victory, they recovered quickly. Within six minutes they were level.
The ball fell to Kagawa 35 yards from goal and he threaded a pass to Rooney, who calmly passed the ball into the net past Boruc.
It was a breathless start to the game, with United committed to attack in a 4-2-4 formation, and they could easily have scored twice before they finally got their second goal before the half-hour mark with Kagawa also hitting the post.
Van Persie returned to the side after sitting out the FA Cup win over Fulham and caused havoc with a succession of fizzing free-kicks. From one of them, just before the half-hour, the Dutchman sent the ball to the back post where Patrice Evra nodded it back for Rooney to tuck in from a yard out.
Danny Welbeck and Van Persie could have added further goals before the interval, and with Southampton also throwing men forward, there was no shortage of space.
The introduction of Adam Lallana and Steven Davis brought a measure of control to the visitors' midfield after the break and Lambert, quiet to that point, twice gave De Gea something to think about with long-range shots.
The hosts endured a slack spell, giving the ball away several times and De Gea fumbled another Lambert effort.
It was enough to get Ferguson off his seat and he eventually brought on Rio Ferdinand to replace the struggling Chris Smalling.
Van Persie might have had cause for complaint after his header from Rooney's cross was ruled out for offside, but the hosts and their supporters were relieved enough to hear the final whistle as Southampton ended the game strongly.
Manchester United boss Alex Ferguson told BBC Sport: "[Winning] is the name of the game at this stage of the season.
"For the first 30 minutes I thought we were fantastic, we played really well. But in the second half Southampton have been the best team to play here this season.
"We were fortunate to win the game. They pushed on top of us and didn't give us any time on the ball."
Southampton boss Mauricio Pochettino, speaking through a translator, told BBC Sport: "I'm very proud [of Ferguson's praise]. It's very important for my players to hear. But we leave with no points. We did play well but I'm upset at not getting a draw at least. It doesn't console me.
"I think in the second half we played as we should have done for the whole game. I think it's important for the team to know we can play that well."
Sorry, we were unable to load match stats, please try again.
Live Text Commentary
Full Time The final whistle goes and the game is over.90:00 +2:47
Adam Lallana takes a shot. Nemanja Vidic gets a block in.90:00 +0:31
Header by Jay Rodriguez from deep inside the penalty area misses to the left of the goal.89:10
The ball is sent over by Adam Lallana, clearance made by Danny Welbeck.86:49
The ball is crossed by Luke Shaw.85:33
Adam Lallana gives away a free kick for an unfair challenge on Rafael Da Silva. Rio Ferdinand restarts play with the free kick.85:13
Unfair challenge on Jack Cork by Luis Nani results in a free kick. Direct free kick taken by Jos Hooiveld.84:32
Rickie Lambert takes a shot. Blocked by Nemanja Vidic. Shot from just outside the box by Morgan Schneiderlin goes over the bar.82:27
Direct free kick taken by Adam Lallana.82:27 Booking
Booking Rafael Da Silva is shown a yellow card.82:14
Adam Lallana fouled by Rafael Da Silva, the ref awards a free kick.79:14
Inswinging corner taken right-footed by Wayne Rooney from the left by-line to the near post, Jay Rodriguez manages to make a clearance.78:50
Patrice Evra fouled by Jack Cork, the ref awards a free kick. Michael Carrick takes the direct free kick.77:14 Substitution
Substitution Daniel Fox leaves the field to be replaced by Luke Shaw.75:52
Strike comes in from Rickie Lambert from the free kick, brilliant save by David De Gea.75:52 Booking
Booking Booking for Nemanja Vidic for unsporting behaviour.75:48
Jay Rodriguez fouled by Nemanja Vidic, the ref awards a free kick.74:37
Centre by Luis Nani, Robin van Persie takes a shot. Save made by Artur Boruc. Wayne Rooney delivers the ball. Robin van Persie is ruled offside. Artur Boruc takes the free kick.74:06
A cross is delivered by Patrice Evra.73:39
Patrice Evra delivers the ball, Maya Yoshida makes a clearance.
Substitution (Man Utd) makes a substitution, with Luis Nani coming on for Shinji Kagawa.71:37
Corner taken by Daniel Fox from the left by-line, Nemanja Vidic makes a clearance.71:27
Nathaniel Clyne crosses the ball, Rio Ferdinand makes a clearance.70:29
Wayne Rooney takes a shot. Save by Artur Boruc.69:07
The ball is swung over by Morgan Schneiderlin, clearance by Rafael Da Silva.68:29
Robin van Persie delivers the ball, clearance made by Jos Hooiveld.67:12 Substitution
Substitution Oliveira Anderson goes off and Rafael Da Silva comes on.66:58
Shot from just outside the area by Jay Rodriguez goes over the bar.66:36
Unfair challenge on Maya Yoshida by Robin van Persie results in a free kick. Maya Yoshida takes the direct free kick.62:08
David De Gea takes the free kick.62:08 Substitution
Substitution Rio Ferdinand joins the action as a substitute, replacing Chris Smalling.62:08
Nathaniel Clyne gives away a free kick for an unfair challenge on Patrice Evra.60:43
Morgan Schneiderlin takes a shot. Blocked by Oliveira Anderson. Outswinging corner taken by Daniel Fox, clearance by Wayne Rooney. Steven Davis takes has a header from just inside the penalty box which clears the crossbar.59:41
Free kick awarded for an unfair challenge on Adam Lallana by Michael Carrick. Rickie Lambert shoots direct from the free kick, David De Gea makes a save.57:54
Outswinging corner taken from the right by-line by Morgan Schneiderlin, Rickie Lambert takes a shot. Effort from the edge of the area by Steven Davis goes wide of the right-hand upright.57:42
The ball is delivered by Jay Rodriguez, blocked by Patrice Evra.57:01
Outswinging corner taken right-footed by Morgan Schneiderlin from the right by-line, clearance by Danny Welbeck.55:54
Maya Yoshida fouled by Danny Welbeck, the ref awards a free kick. Direct free kick taken by Jos Hooiveld.54:35
Shinji Kagawa produces a cross, Jos Hooiveld manages to make a clearance.53:18
Rickie Lambert produces a right-footed shot from just outside the area that goes harmlessly over the target.52:33
Outswinging corner taken left-footed by Daniel Fox from the left by-line to the near post, Maya Yoshida takes a shot. David De Gea makes a comfortable save.50:38
Jay Rodriguez challenges Patrice Evra unfairly and gives away a free kick. Free kick taken by Oliveira Anderson.49:45
The referee blows for offside. Artur Boruc restarts play with the free kick.49:00
Rickie Lambert takes a shot. Comfortable save by David De Gea.48:44
Jay Rodriguez takes a shot. Nemanja Vidic gets a block in.45:38
Adam Lallana produces a cross, clearance by Nemanja Vidic.45:01
The game restarts for the second half.45:01 Substitution
Substitution (Southampton) makes a substitution, with Adam Lallana coming on for Gaston Ramirez.45:01 Substitution
Substitution Steven Davis replaces Jason Puncheon.45:00 +1:52 Half time
Half Time The ref blows to end the first period.44:08
Robin van Persie crosses the ball from the free kick left-footed from right channel.44:08 Booking
Booking The referee books Morgan Schneiderlin for unsporting behaviour.43:59
Foul by Morgan Schneiderlin on Phil Jones, free kick awarded.43:28
Shinji Kagawa fouled by Nathaniel Clyne, the ref awards a free kick. Patrice Evra takes the free kick.41:51
Inswinging corner taken left-footed by Daniel Fox.40:16
Foul by Gaston Ramirez on Nemanja Vidic, free kick awarded. Free kick taken by Nemanja Vidic.39:55
Wayne Rooney takes a shot. Artur Boruc makes a save.39:35
Danny Welbeck takes a shot. Save by Artur Boruc.37:36
Gaston Ramirez sends in a cross, clearance by Phil Jones.37:15
Robin van Persie crosses the ball, Jos Hooiveld manages to make a clearance.36:34
Handball decision goes against Jason Puncheon. Indirect free kick taken by David De Gea.35:30
Foul by Robin van Persie on Nathaniel Clyne, free kick awarded. Nathaniel Clyne takes the direct free kick.34:34
Free kick awarded for a foul by Jack Cork on Patrice Evra. Shinji Kagawa takes the direct free kick.33:28
Corner from the left by-line taken by Morgan Schneiderlin, Header on goal by Rickie Lambert from inside the box goes harmlessly over the target.33:05
Jay Rodriguez takes a shot. Blocked by Michael Carrick.30:35
Robin van Persie produces a left-footed shot from inside the area that goes over the bar.29:33
Rickie Lambert fouled by Nemanja Vidic, the ref awards a free kick. Direct free kick taken by Morgan Schneiderlin.29:05
Patrice Evra produces a left-footed shot from the edge of the area and misses to the left of the target.28:38
The ball is delivered by Phil Jones, Jos Hooiveld makes a clearance.26:09
The assist for the goal came from Patrice Evra.26:09 Goal scored
Goal! - Wayne Rooney - Man Utd 2 - 1 Southamp'n Wayne Rooney gets on the score sheet with a goal from close in low into the middle of the goal. Man Utd 2-1 Southampton.25:19
Free kick awarded for a foul by Jay Rodriguez on Phil Jones. Centre by Robin van Persie,23:55
Wayne Rooney crosses the ball, save by Artur Boruc.22:05
Inswinging corner taken left-footed by Robin van Persie from the right by-line, save by Artur Boruc.21:41
Robin van Persie takes a shot. Maya Yoshida gets a block in.19:26
Inswinging corner taken right-footed by Wayne Rooney from the left by-line, Maya Yoshida manages to make a clearance.18:58
The ball is delivered by Robin van Persie, Jos Hooiveld manages to make a clearance.17:49
Gaston Ramirez is flagged offside by the assistant referee. Indirect free kick taken by Chris Smalling.16:23
Free kick awarded for a foul by Nemanja Vidic on Jason Puncheon. Gaston Ramirez has a direct shot on goal from the free kick.14:12
Jay Rodriguez gives away a free kick for an unfair challenge on Phil Jones. The free kick is delivered left-footed by Robin van Persie from right wing.13:15
Jack Cork takes a shot. Blocked by Robin van Persie.13:02
Outswinging corner taken left-footed by Gaston Ramirez, clearance by Wayne Rooney.11:59
Michael Carrick concedes a free kick for a foul on Gaston Ramirez. Direct strike on goal from the free kick comes in from Rickie Lambert, blocked by Danny Welbeck.10:12
The referee blows for offside against Shinji Kagawa. Jason Puncheon restarts play with the free kick.9:42
Phil Jones sends in a cross, Shot from close range by Shinji Kagawa bounces off the post.7:44
The assist for the goal came from Shinji Kagawa.7:44 Goal scored
Goal! - Wayne Rooney - Man Utd 1 - 1 Southamp'n Wayne Rooney finds the net with a goal from close in to the bottom left corner of the goal. Man Utd 1-1 Southampton.4:22
Wayne Rooney takes the inswinging corner, Header on goal by Chris Smalling from inside the box goes harmlessly over the target.2:09 Goal scored
Goal! - Jay Rodriguez - Man Utd 0 - 1 Southamp'n Jay Rodriguez scores a goal from inside the six-yard box low into the middle of the goal. Man Utd 0-1 Southampton.0:00
The referee gets the game started.
Live data and text provided by our data suppliers