Full-time. That's it. United pull it out the bag thanks to Robin van Persie. He looked like being the villain but he ends the game as the hero. Heartbreak for Southampton - three straight defeats but such a brilliant effort from them.
Southampton attacking but surely not. Penalty appeals! Ferdinand with a push but Mike Dean isn't giving that one.
Nani finds Van Persie at the near post and he heads past Davis. Slack marking. Incredible forward play - and strength of character to bounce back from the penalty miss.
Goal! Van Persie hat-trick!
Corner for United. Nani will take it.
Hernandez shoots wide.
There will be four minutes added time.
Ward-Prowse with the cross to find Hooiveld but Vidic just does enough. Another corner comes out to Ward-Prowse but his shot is blocked. Then Fox tries a ludicrous effort from distance but he skies it. Had men in the box too.
Corner for Southampton now. They're back on the attack!
Rafael crosses from the right and finds Ferdinand unmarked in the area. The big defender heads against the post but Van Persie is there to put home the rebound with his left foot.
Goal! Van Persie equalises!
Wonderful take from Hernandez to latch onto a long ball. But when he cuts inside Clyne is on the cover and gets there first to concede a corner.
Rafael crosses from deep to find the head of Hernandez but he heads wide under pressure.
United dominating the game now as Southampton retreat. No significant chances since the penalty though.
Hooifeld does well to outpace Hernandez there. Surprising, really. The Mexican looked to be through on goal.
Carrick knocks the ball up to Van Persie but the forward is offside.
The corner comes to nothing and Southampton can break. Rafael commits the foul on Rodriguez. Time to regroup for the home side after that period of pressure.
Good skill from Nani outwits Clyne and he wins the corner after his cross is sliced over the bar by a Southampton defender.
Rodriguez on for Lallana.
Van Persie sees a shot blocked.
Valencia crosses from the right. Evra crosses from the left. Saints withdrawing onto the edge of their area now. Playing on the counter-attack.
Goalscorer Lambert is also going off to be replaced by Guly.
Debutant Mayuka on for the impressive Puncheon.
Carrick crosses this time but it is too strong and runs out of play.
Davis comes off the line to claim well from Scholes' lofted cross.
Hernandez on for Welbeck.
Scholes finds Van Persie who twists and turns down the right channel before firing wide with his right foot. He owes United one here.
What a dramatic game this has been. Saints back on the attack with Lallana but Vidic times the challenge well.
Van Persie went for the dinked penalty and Davis saves it. The keeper redeems himself as he gave the ball away in the build-up to the penalty.
And Van Persie misses the penalty!
Penalty! Hooifeld slides through the back of Van Persie. Awful decision by the defender.
Lambert is away now - he beats the offside trap - and has time. Tries to find Ward-Prowse at the far post but Ferdinand is back to rescue the situation.
This is an astonishing game. So open. Southampton not sitting on this lead, by any means.
Now a wonderful through-ball from Lambert finds Lallana but he is (wrongly) ruled offside.
Clever disguised pass from Lambert finds Lallana but Evra produced a great tackle.
Scholes then tries a longer ball to find Welbeck but Fonte cuts it out with his head.
Scholes' through-ball sends Van Persie away immediately. The Dutchman pulls the trigger but Davis saves.
Nani replaces Kagawa.
Scholes on for Cleverley.
Puncheon in the left channel now but he shoots wildly with men in the box.
Lallana with an effort from the edge of the box but it's easy for Lindegaard. United under serious pressure here.
Davis crosses for Lambert to attack Rafael again at the far post but the little Brazilian is brave this time and heads away well.
The United keeper claims the resulting corner.
Southampton looking for a third. Puncheon skins Evra by surprisingly turning onto his weaker right and drills the ball at the near post but Lindegaard saves.
Good header from Schneiderlin. Lambert crossed right-footed from the left and there was the midfielder. In some ways it was a mirror opposite to Saints' first goal. In others it was a repeat of the United equaliser - like Clyne, Evra slipped to allow Schneiderlin all the freedom he needed.
Goal! Morgan Schneiderlin with a header!
Kelvin Davis with a wretched pass and Valencia intercepts. He lays the ball across to Van Persie who has a good chance to score but slices it wide. Good chance for a top-class striker that.
Cleverley finds Van Persie who holds the ball up well. The ball comes to Evra but his cross is cleared.
Fox thinks he has won a corner but the referee awards a goal-kick to the disgust of the home support.
Vidic is all over Lambert again. Trying to win a header he can't. Foul given.
Puncheon cuts in from the right onto his favoured left foot and is looking to shoot but Carrick blocks bravely.
Then Kagawa and Van Persie link up nicely. Welbeck makes a good run to buy Kagawa space to shoot left-footed but it's just wide.
Vidic tries to find Rafael bursting forward but the pass is too strong for the attacking full-back.
Puncheon tries to feed Lambert but the striker is flagged for offside.
Lambert nearly pulls away from Rafael again in similar fashion to how he did for the goal but there is cover this time.
Southampton kick-off and we're underway in this second half.
The big question now is whether Southampton can keep this up. The interval should help as they were tiring and they'll surely be encouraged that their approach is working - but for a Clyne slip they'd be ahead. For United, all they can do is keep passing the ball and hope to find the opening. If it stays as open as it was for periods of that first half then there will be more chances - and you'd fancy the visitors to be more ruthless.
Gabriel says: "To be honest I'm surprised at how close this has been so far. I would have expected Man Utd to be a couple of goals up by now. You've got to hand it to Adkins for how he's motivated his Southampton side with all the talk of Redknapp replacing him over the week."
Half-time. Fantastic half of football at St Mary's. It finishes level.
Van Persie nearly latches on to a long ball but again he cannot bring the ball down under pressure.
There will be one minute added time.
Saints beginning to tire now and you sense they need the half-time whistle. They've worked so hard here.
United have numbers in the attack but Kagawa's ball to Van Persie is too difficult for the forward to bring down and the chance is gone.
Schneiderlin has a chance to put Lallana clear on goal but the pass is just behind him. He has to delay and that allows Carrick to intercept.
As they do so, a cross comes in from Valencia and - incredibly - Clyne slips again! Evra has a free header but Davis saves.
United desperate to take the sting out of this one with a period of possession.
Valencia nearly gets away down the right but the covering defender is alert and the chance is snuffed out.
Passing statistics show this as 50:50 and that speaks volumes for Southampton's efforts here, especially as United dominated the early minutes.
Schneiderlin nearly finds Fonte in the right channel. The centre-back was still up from the free-kick. It just runs through to Lindegaard.
Vidic with a foul on Lambert. The big forward used all his nous there to win that one.
Lindegaard with a poor kick, surrenders possession.
Lallana with an effort now, just wide of the right-hand post. More good football.
Carrick is robbed in a dangerous area and Saints are still pressing well. More than holding their own here.
Ward-Prowse with a quick one-two and gets his shot off just wide of the post.
Clever reverse pass from Puncheon in behind the United defence to find Lallana. The Saints man turns well but his right-footed cross is too strong for Lambert.
Van Persie with the dinked free-kick but that's wide. It was a good area too.
Valencia cuts the ball back for Welbeck and he is fouled by Fonte on the edge of the box.
Welbeck lays the ball sideways across the box towards Van Persie and he tries to curl one into the top corner but gets it wrong and that's over the bar.
Nice body sway from Welbeck but he is crowded out. This is a cracking game with chances at both ends.
Excellent football from Southampton again as they spread the ball wide to Lallana on the left. His cross is cleared but only as far as Lambert who fires a left-footed effort just wide of Lindegaard's left-hand post.
Clyne fell over as Valencia's cross came across the box and that allowed Van Persie time and space to pick his spot.
Goal! Robin van Persie with a neat left-footed finish!
United enjoy a long spell of possession in the Saints half but it ends with Evra lofting in a cross that Davis claims easily.
Shot from Kagawa from distance and Davis has to turn it behind for a corner. It comes to nothing.
Hooiveld with a long ball towards Lambert and they are nearly in behind United but Vidic head back to his keeper under pressure.
Fantastic football from Southampton now - even some showboating from Ward-Prowse!
United trying to regain a measure of control but Saints are continuing to press them. The hosts are backing off Carrick but then pressing the next pass hard and United struggling to find a way through.
Puncheon with a left-footed cross from the right finds Lambert who has pulled onto Rafael at the far post. The header is superb and Lindegaard has no chance.
Goal! Rickie Lambert with a powerful header at the far post!
Schneiderlin with a left-footed effort from distance but it's well over the bar.
The corner is a clever one. Saints put all their targets on the line and that allows Lallana to pull away to shoot from 12 yards out when the cross comes in low. He doesn't quite connect and skews his effort wide.
Clyne's cross is deflected and Carrick cannot prevent the corner.
Now it's United defending and trying to break. Welbeck has the chance to do so but Puncheon fouls.
Good pressure from the home side. They're really growing into it.
Puncheon crosses for Lambert at the far post but the forward can only head tamely at Lindegaard. The ball was a little high for him.
Now Ferdinand is troubled by Lambert and forced into a desperate clearance.
Southampton have settled a little now and Lindegaard has to dash off his line after Ward-Prowse turns Vidic impressively.
Lofted pass from Carrick into the left channel. Van Persie chests the ball and tries to volley first time but it drifts wide of the far post.
Strong header from Vidic. The home side struggling to get the ball up to Lambert in the early stages.
Delightful flick from Van Persie nearly finds Kagawa in the box but the Japan international slips.
Lallana has the chance to run at Rafael but the full-back is up to the challenge and wins a throw-in.
The delivery is poor and hits the first man. First spell of possession for Saints now.
Van Persie's corner is cleared but United soon win a free-kick on the right so the Dutchman will whip it in again...
Good interchange between Valencia and Kagawa brings a corner for United on the right.
Carrick's happy to be in midfield - he's charging up the pitch as United attack early on.
United kick-off at St Mary's.
The players are out and we'll be underway shortly. Vidic and Ferdinand paired together. How Ferguson must wish he could have done that more often in recent seasons.
Thanks for all your feedback. Sorry i couldn't post them all up. The players are in the tunnel and we're nearly ready to go.
Joshua: "Easy win for United today 3-1 with Van Persie scoring twice."
Chris: "I reckon there will be a United rout today! 5-0 with Kagawa getting a brace."
Ben: "I'm going for a 0-2 United away win, RVP getting both of the goals."
Ahmed: "Man Utd team looks good, I especially like the look of Kagawa but I will go for a surprise win for Southampton - a Lambert brace." That would be interesting.
Iacovos: "Why does Fergie keep playing Welbeck on the left? Last time he was effective was Sunderland's win at Stamford Bridge a while back now..."
Jamie Redknapp says it's not going to do De Gea's confidence much good. Thoughts?
Geoff Shreeves interviewing Sir Alex Ferguson on Sky Sports now. The United boss mentioned that error against Fulham by De Gea and claims it could have cost the Red Devils the game. He didn't get to 1000 games without being ruthless.
Lots of you wondering what De Gea has done wrong. There was the mix-up with Vidic against Fulham. Squad rotation and all that?
Richard says he 'can't believe it's not Buttner at left-back'. He cracked a funny.
Ben: "Glad to see that Ferdinand has made a surprise return to the defence. No real surprise with the rest of the team, Carrick will slip back into midfield and Danny Welbeck has a chance to make a name for himself with Rooney's spell on the sides. Also a shock to see Lindegaard get the nod ahead of De Gea after his impressive shot stopping in the opening games.. 3-1 away win for the Reds!"
Lots predicting 3-0 United with Van Persie and Kagawa in the goals. Any Saints fans feeling confident? Spirited effort against City on the opening weekend but back down to earth last weekend at home to Wigan. Tough start for Nigel Adkins.
Morgan: "Can't see anything other than a United win, with RVP adding to his tally. Hope we can score a few to celebrate Fergie's 1000th league game in charge."
Tyler: "I'm a United fan but I think we will just scrape the win 2-1. Van Persie and Kagawa for United and Rickie Lambert for Southampton."
Lewis says: "Looking forward to the game today, very shocked about Sir Alex's choice of goalkeeper this afternoon, but who can question him after so much success over the years, looking forward to seeing RVP in a United shirt once again and also Kagawa who looks a very good player, I think United will come out on top today with a 0-3 victory!"
Our friends at Sky Bet have Manchester United at 1/2 for the win with Southampton out at 11/2. The draw is available at 100/30.
Saints make two changes to the team that lost at home to Wigan. James Ward-Prowse is back in the starting line-up alongside Jason Puncheon. Jay Rodriguez and Guly do Prado are the men to miss out.
Interesting team selection from Sir Alex Ferguson. Anders Lindegaard is in for David de Gea, while Rio Ferdinand is fit despite suggestions to the contrary from the United boss.
Any thought on those selections or predictions for the game? Let me know by email at firstname.lastname@example.org or on Twitter at @GhostGoal.
Southampton: K.Davis; Clyne, Fonte, Hooiveld, Fox; Ward-Prowse, Schneiderlin, S.Davis, Puncheon, Lallana; Lambert.
Man Utd: Lindegaard; Rafael, Ferdinand, Vidic, Evra; Valencia, Carrick, Cleverley, Kagawa; Welbeck, Van Persie.
The teams are in and will be up shortly.
Welcome to our live commentary from the Premier League as Southampton host Manchester United at St Mary's.
Live updates will appear here from 1600 BST...