Yaya Toure converted from the penalty spot with just two minutes played to give the hosts the lead before the Saints levelled things up on 36 minutes thanks to a penalty from Rickie Lambert.
However, goals from Samir Nasri and Edin Dzeko in first-half stoppage time saw City take control of the match heading into the second period.
The home side then sealed the points with 10 minutes left to play as substitute Stevan Jovetic tapped in Jesus Navas's cross.
Read Sports Mole's minute-by-minute report below to find out how the action unfolded at the Etihad Stadium.
11.45amHello there and welcome to Sports Mole's live text coverage of this afternoon's Premier League encounter as Manchester City welcome Southampton to the Etihad Stadium. We should have some team news for you shortly.
11.48amThere's plenty at stake in this match today, not least for Man City. Manuel Pellegrini's side have to win this if they want to keep pressure on Liverpool and Chelsea in the Premier League title race. The Blues will move up to second place in the standings if they come away with the points this afternoon.
11.51amHowever, City are coming up against a Southampton team full of confidence. The Saints will remain in eighth place even if they win today, but three points would do their bid for European qualification the power of good. They're not expected to come away with anything this afternoon, though they are more than capable of worrying their hosts.
12.04pmSouthampton boss Mauricio Pochettino has made two changes to his starting XI on the back of last weekend's 4-0 rout of Newcastle United. Artur Boruc misses out in goal due to a slight back problem, so Paulo Gazzaniga replaces him between the sticks. Elsewhere, Morgan Schneiderlin comes in for James Ward-Prowse.
12.13pmMan City's last defeat in the Premier League came at the start of February when they were beaten 1-0 at home by Chelsea. Since then, the Blues have taken 14 points from a possible 18. In contrast, Southampton's form has been fairly erratic as of late. The Saints have won three and lost three of their last six games.
12.16pmSouthampton boss Mauricio Pochettino recently speaking to reporters: "Even if we are going to be facing an amazing side like Manchester City we are still a team that likes to play our game and impose our philosophy.
"In the time I have been here we have always shown full respect to the opponents but we are never fearful of who we are playing against.
"We always try to be brave no matter who we are playing - we want to dominate the game but we need to be perfect to get something out of this game."
12.19pmMan City manager Manuel Pellegrini: "[Southampton] are a very good team. They are playing without pressure, they are in a comfortable situation in the table.
"They cannot arrive in Europe, they cannot be relegated, they have very good players and a very good manager. We are absolutely sure we are going to have a tough game on Saturday."
12.24pmHEAD TO HEAD: It's Southampton who narrowly lead the head-to-head record between these teams, winning 27 matches compared to Man City's 24. The side have also played out 23 draws.
12.27pmWhen it comes to more recent meetings, Man City have the edge with three wins from their last six games. Southampton have earned one victory, while there have been two draws. The most recent match came at St Mary's Stadium back in December where the spoils were shared in a 1-1 draw.
12.30pmREFEREE WATCH: The man in charge of today's match at the Etihad Stadium is Chris Foy, who has dished out 51 yellow cards and six red cards in 19 games this season.
12.35pmAround 10 minutes to go until this match gets underway and the atmosphere is building nicely inside the Etihad Stadium. While a win is what Man City ideally want, a draw would not be completely damaging in terms of their title chances. However, they really need to keep the pressure on Chelsea and especially Liverpool, who are experiencing some devastating form at the moment.
12.38pmPREDICTION TIME: Today's match has all the makings of an open and entertaining encounter, but we here at Sports Mole can see Man City coming away with the points thanks to a 3-1 victory. Let's hope that these two teams don't disappoint this afternoon.
12.42pmThe players are starting to emerge from the changing rooms as kickoff approaches. Vincent Kompany has the look of a man on a mission at the front of the Man City lineup. Can he lead his side to three vital points? Southampton are sure to have something to say about that if they play to their full potential.
1 minKICKOFF! The teams are out, the pre-match handshakes have been done, and it will be Southampton to get us underway. Here we go!
3 minGOAL! MAN CITY 1-0 SOUTHAMPTON (TOURE, PENALTY)
3 minWhat a start for the hosts as they take the lead through Yaya Toure's penalty! The initial incident saw Dzeko tripped by Fonte inside the box. You could claim that it was a bit of a soft one, but Chris Foy didn't hesitate in awarding the spot-kick. Toure then stepped up to send Gazzaniga the wrong way.
4 minCHANCE! Almost a second for Man City, who are looking rampant. Zabaleta did well down the right before surging into the penalty area. His pass found Nasri, but the Frenchman could only shoot wide from about 12 yards.
7 minCredit to Southampton as they try to continue playing their creative, flowing football despite going a goal behind so early. However, it's Man City who are firmly on top during these opening few minutes.
9 minA decent opportunity for the visitors there as Rodriguez whips a delicious cross into the box, though it just goes over Lambert's head. An inch or two lower on that cross and the Saints striker would have been looking to bury that past Hart.
12 minSouthampton are definitely starting to play their way into this match. They win a couple of corners in quick succession, though they fail to really trouble the Man City defence with either of them. Still, they're not allowing the hosts too much possession right now. City have dropped off a bit in terms of tempo.
15 minCHANCE! That could so easily have been 1-1 right there. Lambert floated a wonderful pass over the Man City defence and into the path of Lallana, but the Saints captain just couldn't control it. The ball ran out of play in the end, though it was nearly so much more.
18 minYou would expect that early Man City goal to have calmed the home fans down, but there's plenty of apprehension in the stands at the Etihad Stadium this afternoon. They know that Southampton are a genuine threat and aren't afraid to attack. The visitors create another opening as Chambers crosses from the right towards Lallana, who volleys over from a tough angle.
21 minThe Southampton players are everywhere at the moment. They're picking up every loose ball and refusing to allow Man City to get comfortable. It's a struggle to tell who is the home side right now. That said, it's City who still lead as we get past the 20-minute mark.
25 minSUBSTITUTION: Bad news for Southampton here as Jay Rodriguez is stretchered off with what looks like a nasty knee injury. The forward landed awkwardly after bringing a long ball down, and he knew straight away that it wasn't good. What a shame for the youngster. Could that also have repercussions for England? Roy Hodgson is in the crowd today. Rodriguez is replaced by James Ward-Prowse.
27 minCHANCE! That's a decent effort from Lambert, who curls a free kick narrowly wide of Hart's near post. Southampton don't look too rattled following that injury to Rodriguez, though only time will tell how it affects them tactically.
30 minMan City look as if they're ready to gain a bit more control over this match now. They threaten the visitors after some neat build-up play as Navas lashes a half-volley off target from the edge of the box. Around 15 minutes of normal time left in this first half.
34 minIt's backs against the wall for Southampton now as Man City go in search of a second goal. Navas and Silva both have a couple of efforts from the edge of the box, but the Saints defence stands firm to block both of them. A dangerous free kick out on the right is then delivered to the back post by Nasri, only for Dzeko to head over from close range. That was a terrible miss.
36 minGOAL! MAN CITY 1-1 SOUTHAMPTON (LAMBERT, PENALTY)
36 minNow it's Southampton's turn to score from the spot as Rickie Lambert powers the ball past Hart following Zabaleta's trip on Cork. Man City think that it's a bit of a soft decision from Chris Foy, but the replays would suggest that the youngster was fouled by the right-back. Game on!
40 minTruth be told, Southampton fully deserve to be level in this match. They've dominated for large spells with some daring, attacking football while Man City have struggled to get out of second gear. The Etihad Stadium is stunned. However, the hosts have plenty of time to rectify this situation. One can only imagine that Manuel Pellegrini will give his players a piece of his mind during the interval.
43 minThe Saints are really heaping the pressure on Man City now as we approach half time. They're putting some dangerous crosses into the box from wide positions, that the home defence are just about dealing with.
45 minThe hosts are back in front, though it's hard to say that they deserve it. Either way, it's a lovely goal from Samir Nasri. Toure's pass to Dzeko was flicked through to Silva, who crossed to Nasri to tap in from close range. There was a hint of offside in the build-up.
45+3 minWhat an end to the half from Man City as Edin Dzeko makes it 3-1! Some patient passing from the hosts allowed Kolarov to receive the ball out on the left side. The full-back crossed into a really dangerous area, allowing Dzeko to head in. Incredible stuff.
1.37pmWhat an amazing 45 minutes at the Etihad Stadium as Man City lead 3-1. Yaya Toure's penalty put the hosts in front before a Rickie Lambert got Southampton level. The visitors were the better team overall, but they were punished twice in stoppage time when Samir Nasri and Edin Dzeko both netted to give the Blues control.
1.43pmLet's be honest here: Man City were well below par in that first half. Southampton were easily the better team, but they will be scratching their heads wondering how they're 3-1 down. They didn't allow Jay Rodriguez's serious knee injury to affect them, though it's a couple of clinical Man City attacks that have made the difference.
1.46pmSouthampton will probably be feeling a bit aggrieved at the nature of Man City's second goal as Silva was a mile offside in the build-up. However, the linesman failed to notice the Spaniard's advanced position before he set up Nasri. Mauricio Pochettino may well say something about that after the match.
1.49pmIt looks at the moment as if Man City will be coming away with the points from this match, but an early goal for the visitors could change everything. One thing you can expect if for the Saints not to change their style of inventive, incisive football.
46 minSECOND HALF UNDERWAY! The players are back out and it will be Man City to kick us off for this second half. The hosts have also made change during the interval, with Javi Garcia coming on for Fernandinho.
49 minIt's been a bright start to the second half from Man City as they look to extend their advantage even further. A dynamic run from Toure sees the Ivorian play in Zabaleta down the right, but the Argentine's cross is gathered by Gazzaniga.
53 minPENALTY APPEAL! Man City want another penalty as Toure is barged into by Lovren inside the box, but Chris Foy waves play on. Toure is not best pleased, though it would have been a harsh one had it been given. The Ivorian went down pretty easily there. The hosts are still on top.
56 minA great move from Man City there as Silva and Nasri link well down the right before the latter picks out Kolarov on the edge of the box. The full-back takes a touch before launching the ball towards goal, but the Southampton defence block his effort. The visitors are playing a dangerous game at the moment, giving the ball away once too often.
59 minSAVE! Oh, that should be 4-1 as Dzeko fails to convert. The striker was played in down the left, allowing him a free run into the Southampton box. His initial effort was well saved by Gazzaniga from close range before he sliced the rebound well off target.
62 minJust under half an hour to play at the Etihad Stadium, but Southampton are offering very little in an attacking sense. While they played some wonderfully free-flowing football in the opening 45 minutes, they've struggled since the restart.
65 minSUBSTITUTION: A straight swap for Man City as Alvaro Negredo enters the action in place of Edin Dzeko. Can the Spaniard help the hosts to kill this game off?
67 minYELLOW CARD! Javi Garcia goes into the book following a trip on Lallana with Southampton looking to break.. No complaints from anyone there.
70 minSouthampton are playing with a very high defensive line right now as they look for a way back into this match, allowing Man City to take full advantage. The hosts are beginning to have a lot of luck running in behind their opponents.
73 minTime is running out for Southampton now. Just over 15 minutes remaining at the Etihad Stadium and they aren't really offering too much in an attacking sense. Man City are happily dealing with anything that's thrown their way while posing a bigger threat on the break.
74 minCHANCE! So close for Southampton, their best opening of the second half by far. Lambert is played in on the angle before dragging his effort narrowly wide of the far post. That was inches away. Meanwhile, the Saints make a change as Sam Gallagher replaces Steven Davis.
76 minSUBSTITUTION: Another swap for Man City here as David Silva goes off for Stevan Jovetic. The Spaniard is given a rousing ovation as he leaves the pitch.
77 minYELLOW CARD! Man City want a penalty as Toure goes down in the box, but Chris Foy shows the midfielder a yellow card instead for simulation. That's embarrassing for Toure as he clearly dived trying to win his side another spot-kick.
79 minSUBSTITUTION: Southampton's final change of the afternoon sees Jack Cork withdrawn for Victory Wanyama.
80 minGame over now as substitute Stevan Jovetic taps in from close range from Navas's cross. The Spaniard's ball into the area narrowly missed Negredo, but Jovetic was there at the back post to convert.
83 minCredit to Southampton, they've certainly contributed to what has been an entertaining encounter today. However, Man City have been that little bit more clinical in front of goal. The Blues would be the first to admit that they have not performed to their full potential, but it's the points that matter at this stage of the season.
85 minOFF THE POST! Textbook stuff from Toure as he hits a low, curling effort towards goal from the edge of the box. It looks as if the ball is going to nestle in the corner, but Gazzaniga manages to turn the ball onto the post before the Saints clear the danger.
88 minToure was not too happy with Ward-Prowse there after the Southampton midfielder has clipped him high on the leg with a mis-timed challenge. No booking for the youngster though as Chris Foy takes a lenient view of things.
90 minThree minutes of added time are indicated by the fourth official...
2.41pmThe full-time whistle goes and it's Man City who have the points thanks to a 4-1 win. The scoreline may have flattered them in the end, but they will not mind one bit. The Blues are now in second place in the table, one point behind leaders Chelsea. Southampton certainly made a right go of it, though they faded in the second half and just couldn't find a way back into the match.
2.43pmThat's all from our live coverage of today's match, but don't forget that you can follow updates of this afternoon's other Premier League games on Sports Mole. Follow this link and see what takes your fancy. Thanks again for joining us and we hope to see you again soon. Goodbye!