Two goals in first half stoppage time helped Manchester City to claim their 14th victim of the season at the Etihad Stadium.
If Saints thought they faced an uphill battle before the game, then their task was made that little harder within three minutes of play in this contest when City went 1-0 up from the penalty spot.
Yaya Toure got the ball rolling from 12 yards after Jose Fonte was adjudged to have fouled Edin Dzeko in the area, which was an early blow for the visitors who lost first choice goalkeeper Artur Boruc prior to the match with a back injury.
The task was made even harder when Saints then lost Jay Rodriguez too after 26 minutes of play of a spirited first half performance from Mauricio Pochettino’s men.
The valiant display drew a deserved equaliser when Rickie Lambert notched a 36th minute spot kick to level the scores – his 34th consecutive penalty conversion for the club. Saints were good value for 1-1, but were denied the chance to be on par with City going into the break thanks to a two quick goals in stoppage time by Samir Nasri and Edin Dzeko who put substantial daylight between the teams heading into the interval.
The fact that Nasri's effort stood was something that angered the visitors with replays confirming that City's David Silva clearly played the assist from an offside position, but referee Chris Foy was not alerted by one of his assistants, much to the surprise of those around the ground.
Manuel Pellegrini's side had won 19 of the 23 league games in which they have scored first in this season, and they made it 20 of 24, by confirming their comfortable looking scoreline with a fourth goal on 81 minutes when substitute Stevan Jovetic rolled home from six yards out.
Although it was a more even second 45 minutes, where Saints’ battling characteristics were displayed to the full, the hosts were not to be denied a 14th win out of 15 home games in the Barclays Premier League, a success which maintained the visitors’ winless run there since April 2004.
Mauricio Pochettino made two changes from the side that beat Newcastle. There was an enforced switch in goal as Artur Boruc missed out with a back injury, and with Kelvin Davis also still sidelined, it meant that Paulo Gazzaniga made his seventh appearance of the season.
It was the Argentine goalkeeper’s first match since the 3-0 win at Cardiff on Boxing Day, whilst he also played in the reverse of this fixture which finished 1-1 at St Mary’s.
Morgan Schneiderlin returned at the expense of James Ward-Prowse to make his first start since the 4-2 win over Norwich at St Mary’s last month. Gaston Ramirez missed out altogether with an ankle injury.
The hosts were without Sergio Aguero, but named Edin Dzeko in attack, with the Bosnian striker having previously menaced Saints by scoring in two of his three Premier League games against the visitors.
Saints took to the field in their changed strip of black shirts and white shorts before getting the game underway, defending the end housing the travelling support on an overcast afternoon in Manchester.
Adam Lallana and Rickie Lambert got the match started and after the game’s initial ebb and flow, there was an early flashpoint when Dzeko won the hosts a penalty when he went to ground under Jose Fonte’s challenge just inside the area.
With three minutes on the watch, Yaya TOURE stepped up to send Gazzaniga the wrong way from 12 yards, leaving the keeper to make his first touch by picking the ball out of his net.
A shaky couple of moments followed as the visitors tried to clear their lines under the high pressing of a City side with their tails’ up. A neat move involving Jesus Navas and Pablo Zabaleta led to the full-back picking out Samir Nasri for a shot from the edge of the box, which the midfielder curled narrowly wide of the right post.
Saints regrouped and steadily grew back into the contest, playing out from the back and using the outlet offered by Jay Rodriguez running through the middle.
It was then from a position wide on the left where Rodriguez broke free once more to cross invitingly towards Lambert, but the delivery narrowly missed the head of the frontman as he tried to convert past Joe Hart.
A succession of corners earned by the visitors put City under further pressure as Saints’ energy continued to work the hosts’ backline.
Rodriguez couldn’t make a clean connection to another corner taken by Steven Davis, and some further misplaced passes by the home side added to the discomfort felt by the native supporters in spite of their lead.
City’s next chance came from another set piece when they were awarded a free-kick on the left flank, the delivery was met by the head of Aleksandar Kolarov, but his effort cleared the crossbar.
Jesus Navas also skewed a shot wide as City were still unable to test Gazzaniga.
Undeterred, Saints continued to play around their opponents with relative ease. Each pass was greeted by an olé from the away supporters until there was a sickening moment for Saints forward Rodriguez as he suffered a serious looking leg injury as he landed awkwardly when controlling the ball in mid-air.
The striker was stretchered off under a standing ovation from all four corners of the ground, with Saints bringing on James Ward-Prowse in his place after 26 minutes played.
Lallana went to ground after a challenge on the left side of the area, and the resulting free-kick was whipped towards the near post by Lambert, but dropped just shy of the target as the hosts breathed a sigh of relief.
Even without their top scorer on the pitch Saints remained a threat, with Steven Davis moving into a more advanced position just behind Lambert to accommodate Ward-Prowse’s arrival on the right, where the visitors sought to play Lambert in from the flanks.
City offered a reminder of their ability from set pieces again when Nasri’s free-kick from the right was headed against the crossbar by Dzeko who flew in at the far post to meet the cross.
Then on 36 minutes, Saints were offered a way back into the game when they were awarded a penalty after Jack Cork had been taken to ground on the left side of the penalty area.
Up stepped LAMBERT who maintained his 100 per cent conversion rate from the spot for Southampton by finding the right corner of Hart’s goal, beating the keeper who had guessed the right way.
The leveller was no less than the visitors had deserved for their endeavour from a challenging position in the contest, and Pochettino’s men showed no signs of slowing down from there as they applied late pressure from corners, which City struggled to deal with effectively.
Fernandinho was correctly booked for handball, before Schneiderlin bamboozled Yaya Toure in midfield with a couple of dinked touches that led to the City man falling to ground as he struggled to keep up with the Frenchman.
But the light relief turned to pain again for the visitors as four minutes of stoppage time were added on at the end of the half.
City reclaimed their lead on the stroke of 45 when Edin Dzeko played in Silva, who from an offside position, in-turn knocked the ball into NASRI, who converted from close range under Gazzaniga for 2-1.
And if Saints thought that was harsh on their first half display, then they were dealt a further blow deep into stoppage time when Kolarov’s cross from the left touchline was headed in by DZEKO off the right post to make it a two goal margin that City could hardly believe themselves.
HALF-TIME: MANCHESTER CITY 3-1 SOUTHAMPTON
Saints were out early and unchanged from the half-time break, before City followed them out with one change to their side as the booked Fernandinho was replaced by Javi Garcia for the second 45.
The visitors maintained their upbeat and positive approach to the match at the start of the second half, with Lallana playing further forward and Davis now on the left. The skipper twice went close to playing in Lambert, whilst Chambers’ cross from the right was just a fraction overhit.
City looked for a second penalty ten minutes into the new half when Fonte bundled Toure to the floor, but this time referee Foy wasn’t interested, with Saints stemming the tide under the latest wave of pressure from the hosts.
City perhaps ought to have struck again on 59 minutes when Dzeko broke free at the left post to work Gazzaniga, who produced a fine save to his left before getting back to his feet to see Dzeko blaze the rebound over from an acute angle.
Saints showed more spirit to come back again, and won a couple of corners for their efforts on the back of a neat move involving Lambert Chambers and Lallana who all interchanged inside City’s area, with the latter unfortunate to get the chance to make the most of Lambert’s cutback from the byline as his shot was deflected behind.
On 65 minutes, City replaced their third goal scorer Dzeko with Alvaro Negredo to pose a new question of Dejan Lovren and Jose Fonte for the remainder of the game.
Lallana tricked his way through to earn Saints a corner, but at the other end, a low save was required from Gazzaniga to keep David Silva’s low effort out at his near post.
City’s Javi Garcia was booked for a clip on Lallana in midfield as the hosts’ frustrations grew again, and they were thwarted again when Fonte put an impeccably timed block on Negredo as the frontman shaped to shoot inside the area.
Saints went close to reducing the deficit on 75 when Lambert collected Lallana’s cute reverse pass inside the area, and the striker blasted a strike from an acute angle across the face of goal, as the visitors targeted the gap between Demichelis and Kompany at the back.
Sam Gallagher was brought on in place of Davis to try and eke out that space even further, but City soon got wise to the move.
The hosts then made their final change by replacing Silva with Stevan Jovetic with 13 minutes remaining, and soon after, Toure was booked for going to ground again all too easily in a bid to win a penalty for his team.
Saints introduced Victor Wanyama for Cork as play entered the final 10 minutes of action, and moments later City were celebrating for the fourth time in the game.
Navas’s pinpoint cross from the right flank was missed by Negredo, but carried on into the path of JOVETIC who rolled the ball in form close range for 4-1.
Gazzaniga had to be alert to deny City a fifth when he was out quickly to stop Negredo from putting the ball past him in a one-on-one situation, with Saints working hard to keep the score down in the closing stages.
Inside the last five minutes, Yaya Toure struck the base of the post from a cutback inside the area, as City made do with four goals in a game for the fifth time this season.
FULL-TIME: MANCHESTER CITY 4-1 SOUTHAMPTON
Manchester City team: Joe Hart, Pablo Zabaleta, Vincent Kompany (c), Martin Demichelis, Aleksandar Kolarov, Jesus Navas, Fernandinho (Javi Garcia 46), Yaya Toure, Samir Nasri, David Silva (Stevan Jovetic 77), Edin Dzeko (Alvaro Negredo 65)
Unused substitutes: Costel Pantilimon, Joleon Lescott, Micah Richards, James Milner
Goals: Toure (pen), 3; Nasri, 45; Dzeko 45 + 4; Jovetic, 81
Southampton team: Paulo Gazzaniga, Calum Chambers, Jose Fonte, Dejan Lovren, Luke Shaw, Morgan Schneiderlin, Jack Cork (Victor Wanyama 79), Steven Davis (Sam Gallagher 75), Adam Lallana (c), Jay Rodriguez (James Ward-Prowse 26), Rickie Lambert
Unused substitutes: Cody Cropper, Nathaniel Clyne, Guly do Prado, Jos Hooiveld
Goal: Lambert (pen), 36
Referee: Chris Foy