Last Updated: 30/11/14 4:09pm
The fourth official has indicated that there will be five minutes to add on at the end of this second half.
However, City captain Kompany has had to limp off and with no more subs available, the visitors are now down to 10 men.
That third goal for City was similar to their second in that the hard-working Aguero broke clear down their left flank, before playing an inch-perfect cross for Clichy to net at the far post.
GOAL! Clichy scores his first-ever goal for City after yet more good work by Aguero with just two minutes to go.
Wanyama tries his luck with a couple of pot shots from distance, but neither have the power or direction to trouble Hart in City's goal.
And now Southampton break clear themselves, but Pelle just cannot stretch enough to reach Long's enticing looking left-wing centre. A real close call there.
Forster now prevents City from going 3-0 up after Clichy plays a long ball over the top for the striker to run on to after a Southampton corner had been cleared, but with all the time in the world and no covering Saints players to worry about, the Argentina international sees his effort saved by the keeper.
You really feel now that that goal by Lampard has wrapped up all three points for the visitors this afternoon.
That was a great break by City as Southampton tried to pile on the pressure at the other end, with Aguero once again picking out exactly the right pass from his position out on the left wing, before then veteran midfielder took his time to fire accurately into the bottom corner of Forster's goal.
Pelle tries his luck from 25 yards out, but substitute Lampard gets in an important block on the edge of City's penalty area.
Aguero does well to hold the ball up, before then playing Fernandinho through down Southampton's left flank, but the Brazilian can only fire his effort into the side netting.
Having looked at the replays, referee Jones really had little other option than to hand the French centre back a second yellow as Long raced clear on goal.
Mangala is dismissed after picking up his second yellow for bringing down Long as the little Irishman ran through on goal.
Navas tries his luck from the right-hand corner of the Southampton area, but the Spain winger just drags his effort wide of Forster's far post.
And again, Mangala gets a dangerous flick-on at the near post, but there are no City players waiting in the middle to score.
Aguero wins City a left-wing corner after trying to wriggle his way through the entire Saints back four there ...
Substitute Milner wins City a left-wing corner and somehow Aguero pokes the ball over from just two yards out after a neat flick-on by Kompany at the near post. That really should have been game over for City, although maybe Fonte actually got a crucial touch there to deflect the Argentinian's effort over the bar.
OK so we are three quarters of the way through this match, with City still fairly comfortable holding on to their albeit slender 1-0 lead.
But Davis's resultant inswinging free kick from the left is easily cleared by the imperious Kompany at the heart of the City back line.
About half an hour left then here on the south coast and it could be a huge 30 minutes as far as City's season is concerned.
But again, City do well to clear their lines at the near post thanks to a powerful header by Mangala.
Navas is now forced to give away a left-wing corner under pressure from Pelle, and while it comes to nothing, the Saints have immediately won another corner, this time from the right ...
Mane tries a rather optimistic effort from 25 yards out that not surprisingly does not require a save from Hart, with the ball going high over the bar.
Mangala meets Navas's right-wing corner at the near post, but the Frenchman cannot get any direction on his header and it sails harmlessly wide for a goal kick.
Having just looked at the TV replays, Saints goalkeeper Forster was slightly unlucky there as Toure's side-footed effort did take a slight deflection off the onrushing Alderweireld.
A lovely move there by the visitors, who patiently built the play up in and around Southampton's area, before Aguero cleverly pulled the ball back from the Ivory Coast international to simply pass the ball into the back of the net from just outside the box.
Schneiderlin has gone off with a 'tight thigh', according to Sky Sports' touchline reporter Geoff Shreeves.
Great start to this second period made by the Saints, who have been on the front foot right from the word go, as well as almost taking the lead twice with long-range efforts.
And now Tadic goes close too as the little Serb cuts in from the right and fires a low shot just past Hart's far post.
Alderweireld, who has been moved into midfield to replace the departed French holding midfielder Schneiderlin, tries his luck from fully 30 yards out and the Belgium international is not far away either.
And Southampton have made an enforced change at the break, bringing on Yoshida to replace Schneiderlin.
OK everyone, we are about to get under way again here at St Mary's as both teams come out on to the pitch for this second half ...
However, for City boss Pellegrini, the Chilean will be slightly concerned at the way in which the match has developed, although at the same time the visitors really should be leading at the break after being denied a clear-cut spot kick after Aguero was felled in the area by Fonte, only for referee Jones to book the Argentinian for some unknown reason.
And that has been an entertaining opening period on the south coast, and I think that the home side will be very pleased with how the first 45 minutes have gone, especially given that they have come more and more into the game as the match wore on.
Okay, referee Jones blows up for half-time then here at a sunny St Mary's with the scoreline still goalless.
The fourth official has indicated that there will be an additional two minutes to be played at the end of this first half.
Having said that, the visitors have been a denied a stonewall penalty that could have altered the course of this game.
It has been a half of two halves really, with City dominating the first part of this opening period, before Southampton then took over for the second part.
However, Hart gets his fist to that inswinging Davis set piece from the left and City can breathe a sigh of relief.
Confusion in the City area there as Hart comes to claim a left-wing centre, only for Mangala to instead give away a needless corner.
A brilliant flick there by Aguero leads to a City corner from their right, but it comes to nothing as Southampton get a head on the cross at the far post and the danger is cleared.
You get the feeling that the first goal this afternoon is going to be absolutely crucial to the outcome of this fixture ...
This is now a really even contest as it is Southampton's turn to appeal for a penalty for a possible Mangala handball, but it is only a corner says referee Jones.
Pelle comes close to ending his recent drought in front of goal after getting a near-post flick on a left-wing corner by Davis, only for it sail just past Hart's far post.
Yet again referee Jones says that Aguero was looking for a free kick right on the edge of Southampton's area after Alderweireld appeared to push the frontman over.
A second incredible penalty-box scramble, this time involving City after Nasri plays Jovetic through on goal on the left-hand channel, only for Forster to make a half block, before Alderweireld completes the job with a last-gasp clearance off the line.
A rarity there as Aguero breaks clear of the Saints midfield, only for the Argentinian to fire his shot high over Forster's crossbar when he could perhaps have played one of his team-mates through on goal.
It is a much more even contest now. In fact, the Saints are the team now in charge of proceedings as Hart is forced to punch clear a dangerous-looking inswinging free kick by Davis. Good goalkeeping there by the England No. 1.
Southampton appear to have weathered that early City storm and are coming into this match more and more, which in turn is raising the home fans' hopes.
Mangala is now booked for a late tackle on Tadic, meaning that the France international has now picked up his fifth booking of the season and will miss City's next Premier League match in midweek.
Having said that, Pelle very nearly gives Southampton what would have been a thoroughly undeserved lead after being picked out unmarked on the penalty spot by a lovely ball from Mane, but the Italian cannot beat Hart, before City somehow manage to clear their lines.
Both City centre backs, Kompany and Mangala, are virtually playing on the halfway line at the moment, which is keeping the home side penned in their own half with nowhere to go when they do eventually get the ball.
If the match continues like this, it will not be long surely before City's pressure tells and they make a deserved breakthrough ...
And Temi Adams rather unsurprisingly says: 'As a manutd fan.I hope and pray that this match ends in a 1-1 draw.'
Meanwhile, Ivorian powerhouse Toure now tries his luck with a pot shot from 20 yards out that Forster simply plucks out of the sky just under his crossbar.
However while the scoreline remains goalless, I do not think that Koeman will be too concerned about City's pressure on his side's goal so far ...
Another dangerous cross from the right by Zabaleta, who is basically playing as an out-and-out right winger at present, with the ever-busy Fonte doing well again to clear his lines at the near post.
It has been all City in these opening 10 minutes, with the home team having barely made it out of their own half so far ... and yet it was the visitors who had the exertion of having to play Bayern Munich in the Champions League in midweek while the Saints have had the past week off.
Incredible decision there just then by the man in the middle and while we do have the benefit of TV replays, it appeared to be a clear-cut penalty on first viewing.
Aguero now gets booked after being fouled in the area by Fonte, but somehow refree Jones though the City striker was diving when in actual fact it was a clear spot kick to the visitors.
But Nasri wastes the chance after trying to be too cute in slipping Aguero free down the channel, only for the Saints back line to read his intentions and clear their lines ...
Wanyama gets an early caution after bringing down the marauding Toure when in full stride. No real complaints there and a free kick now to City in a promising position 25 yards out and central ...
City win a dangerous free kick right by the Saints' corner flag on the left, but it is headed clear powerfully by Fonte at the near post ...
The returning Nasri appears to have a bit of a floating role early on, with the Frenchman popping up on both the left and right flanks ...
Although Koeman and his payers will not be too bothered as they do like to play on the counterattack against the so-called 'bigger' teams ...
City have started well in these opening exchanges, playing most of the match so far in the Southampton half.
Meanwhile, Michael Bowers says: 'I'd LOVE Southampton to do well and win. But I think a 3-3 draw. Then Chelsea's draw with us doesn't look so bad for them.'
Meanwhile, the visitors are able to call upon both Yaya Toure and Fernandinho after the midfield duo were suspended for their midweek win over Bayern Munich. However, the likes of Aleksandar Kolarov and David Silva are both still injured.
The home team welcome back Steven Davis after the holding midfielder missed Monday night's 1-1 draw at Aston Villa with a hamstring problem, otherwise Koeman has no new injury worries to concern him.
Right, less than 10 minutes to go until kick-off then here at St Mary's, so let's just have a quick recap of the team news ...
Key players for Southampton today? Nathaniel Clyne, Fraser Forster, Jose Fonte and Ryan Bertrand have played every minute of every game for the Saints in the Premier League this season ...
There is a real sense of excitement surrounding this afternoon's fixture at St Mary's, especially if you are a Saints fan - are Koeman and Co the real deal, or in fact punching above their weight at present? Let us know your thoughts ...
So Southampton's central-defensive duo of Alderweireld and Fonte will know that they will need to have eyes in the back of their heads this afternoon if they are to prevent Aguero adding to those already impressive numbers.
Today's match will be Kun's 100th Premier League appearance and only Ruud van Nistelrooy (68) and Alan Shearer (79) have a higher tally of goals in their first 100 appearances than he has currently netted in his 99 games (64).
Southampton head coach Koeman has quite rightly likened City striker Sergio Aguero to the Dutchman's former team-mate at both PSV Eindhoven and Barcelona, Romario, and if you look at the little Argentinian's goalscoring stats, then you can see why ...
However, that will be no easy task for the north-west outfit, especially given that the Saints have won six and lost none of their last eight Premier League home games, conceding just two goals in total in the process.
Now if the visitors are able to become the first team this season to come away from St Mary's with three points in the Premier League, then they will move above their opponents into second place in the table, while also managing to close the gap at the top on runaway leaders Chelsea to a more manageable six points.
Now if any of you wish to get in contact with me regarding today's game, then hit me up on Twitter ... @RichieReds1976
Interesting stat that only Chelsea, with 218 tackles, have won more than Southampton's 205 in the Premier League this campaign.
For one thing, the high-flying home side have new left-back Ryan Bertrand once again lining up in defence against City, with the Englishman having made two assists in the Premier League this season. In fact, the only defender with more is Leighton Baines on six.
Saints boss Ronald Koeman is now giving his pre-match thoughts in the tunnel to Sky Sports' Geoff Shreeves about today's huge game, with the Dutchman seemingly confident about his side's chances against the champions. And so he should be ...
Man City: Hart; Zabaleta, Kompany, Mangala, Clichy; Navas, Fernandinho, Toure, Nasri; Jovetic, Aguero.
Southampton: Forster; Clyne, Fonte, Alderweireld, Bertrand; Schneiderlin, Wanyama; S.Davis, Tadic, Mane; Pelle
Good afternoon everyone and welcome to this afternoon's much-anticipated Premier League clash between Southampton and Manchester City from a bright and breezy St Mary's Stadium.