Thanks for tuning in this evening. Stay with Sky Sports for the full match report and all the reaction.
19.26 That's it! Southampton beat Manchester City 3-1!
Southampton are content to share passes in midfield as they see out the remaining minutes. It looks like this is all over for City...
Superb defending from Hooiveld as he intervenes on a dangerous-looking break from Maicon down the right.
Southampton win a free-kick inside their own end to ease their nerves in these dying minutes. Yoshida's long ball is nodded out for a Saints throw.
Barry and Toure trade passes in the middle of the park, still hunting some kind of comeback as the minutes count down.
Zabaleta wins a corner for City in these dying minutes, which Kolarov hurries to take on the right. Five minutes of stoppage time are added, much to the annoyance of the home faithful.
We're into the final minute of regular time. Yaya Toure feeds Maicon in midfield and he tries to build something down the right.
The Southampton home fans are still singing and they really will have something to sing about if the home side can hold on for two more minutes. Zabaleta and Maicon trade passes, looking for a way through in midfield.
A good ball into the box from Clichy just eludes Aguero and is instead picked up by Dzeko. City are running out of time to turn this around.
City give away a free-kick in midfield as Schneiderlin is caught by Milner. Ward-Prowse loses out to Kolarov as City pick up possession.
There's a heart-in-mouth moment for City as Rodriguez is picked out by a Cork pass in bags of space in front of goal but the offside flag is up.
Milner hooks the ball through the legs of Richardson and out to hand Southampton a throw-in.
Lallana breaks down the right and Southampton players pile into the box but City manage to stop him getting a cross away.
Clichy lifts in another ball and it's Hooiveld this time that gets on the end of it in the box, subduing the threat.
Clichy's long ball up the pitch into the box is dealt with by Yoshida. Another ball in towards Dzeko seconds later is seen away by Cork.
81 Goalscorer Steven Davis is brought off and replaced by youngster James Ward-Prowse as Southampton make their final change.
A Kolarov corner is dealt with by the Saints defence and Lallana brings down the clearance to release Rodriguez through the middle. Hart comes out to clear.
Hart scoops up the ball in the box under pressure from the advancing Davis and quickly disposes of it upfield.
It's Hooiveld again that threatens to break for the Saints but he's held up in midfield. The home side win a free-kick inside their own half.
Hooiveld does well to get the ball away from Aguero just inside the Southampton half. Zabaleta's throw secodns later is kept in the air by the hosts.
There's a chance for the visitors as Kolarov slides a cross in from the left but Boruc dives to smother the ball to deny the advancing Toure.
Maicon is robbed of possession by Lallana as he tries to find a way through down the right wing. Southampton are keeping them at bay up to now.
74 Silva comes off for Maicon as City make another change.
Lambert slips the ball to Cork on the edge of the area but he hesitates before taking a shot and, under pressure, skews his effort into the stands.
Southampton win a throw on the left of the City end and Lambert looks for a way into the box but can only feed Schneiderlin down the wing.
71 Slight worry for Southampton as Fox goes down injured and the hosts are forced to make a change, with Frazer Richardson replacing him.
70 Schneiderlin goes to ground off Yaya Toure and the returning midfielder's evening gets worse as he goes in the book.
Southampton are being made to work hard as City apply a spell of pressure, with the defence dealing with a Kolarov cross into the box.
Milner takes a corner for City on the right but Fox clears it with a diving header. Zabaleta diffuses a Southampton chance to break.
Silva loses the ball while on a charge but atones for his error as he instantly wins it back.
The flag goes up for offside to halt a City attack. Mancini looks anxious on the touchline as the minutes tick down.
66 Lescott makes way for Kolarov as City make another change.
Chance for Southampton as Lambert tees up Schneiderlin for a shot on the edge of the box and he swings his effort in, but it's off-target.
A questionable goal-kick from Boruc goes straight to Lescott, who rolls it back to Hart. The hosts are soon back on the ball as Davis feeds Lallana on the left.
Trading passes at the back, City look to build something but the Saints get back on the ball, with Clyne slipping through to Lambert.
Lambert shows great strength in midfield, plucking a long ball out of the air ahead of Barry, and Southampton win a throw on the left.
62 Goalscorer Puncheon makes way for Adam Lallana as the Saints make a swap.
Toure's free-kick from distance is slipped through to Silva, who tries a neat pass back to his fellow midfielder. The move doesn't come off as Toure charges forward but ploughs his shot into the stands.
Toure and Silva exchange passes down the right, trying to find a way through, but Southampton snatch back possession. Barry and Puncheon vie in midfield and the former wins City a free-kick.
Saints are preparing to make their first substitution as Lallana readies himself to come on.
Southampton win a free-kick from distance which is planted in by Davis, but City get it quickly away as Clichy breaks.
"Champions? You're having a laugh" is the chant currently ringing out through St Mary's. Hooiveld covers Aguero as he's released into the Saints half and manages to subdue the striker.
City win a corner and Silva's delivery is greeted by Schneiderlin, who heads it to safety.
56 Milner comes on for Nasri in City's first change.
Yaya Toure attempts to chip a cheeky ball into the Saints box and it finds Aguero, who tries to get a shot away but it's blocked.
Southampton are seeing most of the possession so far this half with 61%. The home side are putting more and more pressure on City in the box as Fox and Lambert keep pushing.
Milner is preparing to come on for City as Mancini looks to make his first change. Cork does well to win the ball from Nasri in a tussle on the right of the City half.
Davis tries to pick out Puncheon in the area but can't quite find his man. Fox flicks a cross in, looking for Lambert, but he fails to stop it going behind.
It's own-goal scorer Barry that manages to get his head to the corner to clear. Clyne tries to find a way into the box but City keep him out.
50 Clichy goes into the book after tangling with Puncheon in the corner of City's half and the Saints have a free-kick.
What a disaster this is turning out to be for City. Lambert crosses in but his ball goes behind Puncheon to apparently diffuse the threat but Barry, trying to guide the ball back to Hart in goal, puts through his own net. Nightmare stuff for Mancini's men.
48 GOAL! SOUTHAMPTON! GARETH BARRY OWN-GOAL!
An early chance for Puncheon this half as the ball finds him on the edge of the box but he can't keep his shot down as it flies into the stands.
City try some link-up play down the right as Nasri and Zabaleta combine but Schneiderlin outwits Aguero to get the ball away.
We're back in action at St Mary's as Southampton get things started this half. The Milner shirt is out and waiting to go but there's been no changes as yet from either side.
Time to get back underway. Thanks for the all the feedback, enjoy the second half.
@GambinoDragon - "hope the score stays the same, I'm in for a nice payout if it does! #saints"
@twowoods - "Southampton are playing brilliantly. Deserve points from this game. But will they get any?"
@Hyltzzz tweeted - "Southampton have been the better team so far,& deserve there half time lead,However it should have been a stone wall penalty"
@George_Bourne93 tweeted - "poor first half for city but take nothing away from Southampton #Inspirational"
There'll be plenty of discussion over Southampton being denied a penalty late on that half when Toure brought down Rodriguez - could have been crucial for the hosts.
Jay Hogaro has written in - "I wonder if Joe Hart will get as much stick as De Gea after that mistake. The tabloids might fill with speculation about Mancini buying another goalkeeper. After all he's had a few howlers this season. Then again I doubt much will be said about the matter because he wasn't signed by Fergie. As a Manchester United fan, I'm enjoying this one."
Saints have been brilliant so far - full of energy and working hard all over the pitch - but Dzeko's goal has made sure City are still in it heading into the second half.
I'm interested to know what you've made of that half. Get in touch by emailing firstname.lastname@example.org or Tweet me @SkySportsRachG.
18.19 The whistle blows and it's Southampton 2 Manchester City 1 at the break. It's been an exciting half and the Saints have really thrown down the gauntlet in those opening 45 minutes.
Toure tangles with Rodriguez in the box but referee Martin Atkinson doesn't give a penalty, opting instead to award a corner. The home crowd are furious.
There's a good chance for City as the seconds trickle down this half, with Nasri planting in a cross for Silva, but he can't sort his feet out to get a proper shot away.
Nothing comes from City's set-piece and Southampton break, with Davis crossing for Schneiderlin, who can only drive his shot into the side-netting.
Aguero goes to ground off another Hooiveld challenge and, perhaps harshly, City have a free-kick. Two minutes of stoppage time are added this half.
Fox's delivery makes things awkward for Clichy but Hooiveld commits a foul to give City some breathing space.
Garcia clumsily goes over the top of Lambert and Southampton are handed a free-kick on the left of goal, which Fox goes to take.
The hosts get the ball away from Aguero to subdue a City threat but Toure picks it up again and launches a ball into the box which goes unanswered.
The Saints win two throws in quick succession in midfield, with Clyne planting both in.
The Saints win a corner, which Davis steps up to take again. His delivery eventually falls to Puncheon, who whips in a shot from range, but it's wide.
Zabaleta is key in a counter-attack, picking out Dzeko who has positioned himself in front of goal. It's not the most clinical of finishes but he manages to direct it into the net.
39 GOAL! Dzeko pulls one back for Man City! 2-1!
Clyne tries a shot for Southampton from distance but it goes over for a Saints corner, which City defend.
Boruc lifts a long ball upfield but Nasri pounces to win it. City are driven back, however, with the Saints pressing them into retreat.
Puncheon tries to slip the ball through for Cork after making another run down the right but Garcia is there to intercede.
Mancini is gesticulating wildly on the touchline as City try to find a way back into this. The rain is coming down heavily at St Mary's.
The teams fight to bring the ball down in midfield and it's Southampton that eventually win the battle. Clyne is fouled by Toure for a Saints free-kick.
Yoshida pulls off some super defending to smother Dzeko in the box and diffuse a City attack.
The home side come close again through a great Rodriguez chance, who is just about subdued in the area.
The Saints now have a corner after Barry sends the ball behind but Davis' delivery is dealt with by the City backline.
Lescott, under pressure from Lambert, is forced to put the ball out down the right of the City half and Clyne takes the resulting throw.
Back on the ball, City have to stay focused as Schneiderlin tries to put the defenders under pressure as they trade passes at the back.
A wasted chance for City as Aguero's delivery slams straight into the Southampton wall. The hosts break as Cork makes a run from midfield.
Another decision goes against the Saints as Hooiveld clips Dzeko. City win a free-kick from a dangerous position on the left of goal and on the edge of the box.
28 Lescott is tugged back by Lambert as he makes a charge and the striker goes straight into the referee's book for his efforts.
Nasri chips the ball through for Barry on the right but the covering Yoshida gets it away. City win a throw, quickly taken by Nasri.
Lambert looks to slip another ball towards the box but City's defence hold firm and Zabaleta gets away down the right.
City are looking for a way back into this as they try to build something from the back, but Rodriguez intervenes.
This is not looking good for the Premier League champions and the Southampton faithful are in fine voice after that second goal.
What an absolute howler from Joe Hart! The England goalkeeper fumbles a save from Lambert's shot and Davis is there to follow up from point-blank range.
22 GOAL! DAVIS! SOUTHAMPTON GO 2-0 AHEAD!
Zabaleta gives away a free-kick after a challenge on Rodriguez and is frustrated after he got the ball away.
City win a corner on the left which Silva steps up to take. Fox is there with the crucial headed block at the near post to see the ball away.
Toure charges in to intercept a Southampton throw in the middle of the park and slips through Nasri. A Zabaleta ball into the box from the right is cleared by Hooiveld.
Rodriguez seizes possession in the City end and feeds Fox out on the left as the Saints look for a way through.
City make Southampton's backline a bit nervous as Silva lifts in a free-kick and the Saints have to scramble to clear it, with Dzeko threatening to pounce.
A line from Sky Bet: Despite being a goal down, Man City are still a short price to win at 6/4 with Sky Bet, while a draw can be backed at 5/2. Aguero is the shortest price in the next goalscorers market (4/1).
Aguero slides the ball into the box from the right after controlling it well but there's no-one there to greet it and a chance goes begging.
A long Hart ball is won by Hooiveld but City win a throw on the right of the Saints' half moments later as they continue a spell of pressing.
Toure tries to free Zabaleta on the right with a looping ball but the offside flag goes up to stop the move short.
Aguero makes a run, slipping the ball through to the onrushing Nasri as they approach the box, but the Frenchman's attempted pass back is intercepted comfortably by Hooiveld.
Hooiveld's long ball very nearly picks out Rodriguez after some slack defending from Garcia but it just overshoots him and rolls back to Hart.
Zabaleta sees off the delivery to keep the hosts at bay. Driven backwards, the Saints exchange passes inside their own half.
Clyne slides the ball into the box and it's seen away by Lescott to hand Southampton a corner.
Artur Boruc hoofs the ball up the pitch as Aguero closes in and Puncheon is on the move again down the right channel.
Not the start the reigning champions would have wanted. Hart picks out Zabaleta with a goal-kick as the visitors look to steady the ship.
Puncheon is the mastermind behind that goal as he slides the ball for Rodriguez on the edge of the box but his shot is foiled by Yaya Toure. Puncheon then makes no mistake bundling the rebound home.
7 GOAL! Puncheon for Southampton! 1-0!
Puncheon escapes down the right after dispossessing Barry and Southampton are on the charge...
Barry gets the ball away from Davies to smother his attempted run towards the box. A long, diagonal Yoshida ball upfield finds Puncheon out on the right.
Garcia leaps to win the ball in the air but it's recovered by the Saints again, who win a throw in midfield which is quickly taken by Lambert.
Lescott's long ball finds Dzeko in the Southampton half but a break from the hosts sees Rodriguez charge through the middle off the left-hand side and Hart is forced to quickly collect.
Joe Hart lifts a long delivery upfield, looking for Aguero, but the Southampton defence get the ball away and Fox boots it in the other direction.
The game comes too early for influential City captain Vincent Kompany, who is sitting in the stands at St Mary's this evening.
Lambert poses the first threat as he loiters in the box but Clichy's header sees the ball clear.
We're underway on the South Coast and it's City that get things started, earning an early throw which Pablo Zabaleta takes.
The two teams are out at a sold-out St Mary's and it's almost time to get underway. Enjoy the first half guys.
Thanks for all your feedback, keep it coming at half-time and I'll do my best to publish some more.
The Saints have thrown away 24 points from leading positions this season - more than any other side.
A few stats quickly before kick-off...Southampton have won just one of their last nine home league matches against City - losing five of them - a record that won't inspire much confidence this evening.
@RorySBarnes tweeted - "I think it's gonna be a good one. As good as City are, they always tend to choke against lower-table teams. A goalless draw."
Macauley Fitzgerald says - "Man city will be under pressure today as a draw could put man utd further in front at the top if city can't handle the pressure I go for a 1-1 draw today it won't be easy for city."
Danny Fox and Steven Davis are the two changes made by Southampton, who replace Luke Shaw and Gaston Ramirez after they suffered knocks.
He's one of two changes made by manager Roberto Mancini, with Samir Nasri the other player brought in, while Carlos Tevez misses out on the 18-man squad, reportedly due to family reasons.
Having a more in-depth look at those teams, influential midfielder Yaya Toure returns to Manchester City's starting line-up, having not featured for the champions since New Year's Day due to African Nations Cup duty with Ivory Coast.
Southampton subs: K. Davis (GK), Forren, Ward-Prowse, Lee, Lallana, Richardson, Chaplow.
City subs: Pantilimon, Kolo Toure, Kolarov, Maicon, Rodwell, Sinclair, Milner.
@adrianeastwood0 tweeted - "City need the win tonight, if they fail to produce I Think title hopes will be over. Good too see Yaya back though. Adrian."
Stephen Chamberlain wrote in - "Would like to wish my Nephew Joe Chamberlain a Happy 18th Birthday and he watches Saints have a good game a St Marys today.Saints to win 3-2 Lallana to score 1st..COYReds!!"
We've had plenty of feedback coming in. Here's what you've had to say...
Man City XI: Hart, Zabaleta, Garcia, Lescott, Clichy,Yaya Toure, Barry, Nasri, Silva, Aguero, Dzeko.
Southampton XI: Boruc, Clyne, Yoshida, Hooiveld, Fox, Cork, Schneiderlin, Puncheon, Davis, Rodriguez, Lambert.
Here come the teams then...
I'll be bringing you the team news shortly but first why not get in touch with your thoughts ahead of kick-off at 5.30? You can email email@example.com or Tweet me @SkySportsRachG.
A very good evening all and welcome to our live coverage of Southampton versus Manchester City.