Sergio Aguero Suffers a Bad Looking Knee Injury
Chelsea, one of City's title rivals, looked much better in their 2-0 win over Wigan Athletic, with the Citizens having a bit of improvement to do if they are to stay ahead of the Blues and Manchester United in the title race.
Despite City's dominance, reflected in their 65 percent possession, they failed to create many clear-cut chances on goal.
But that was just one concern for the Eastlands outfit.
Here's five more of Manchester City's reasons for concern despite their win over the Saints.
The Manchester City players probably knew full well they'd need to be on their guard in every Premier League game.
But it's one thing to know it, and another entirely to go out there and do it.
Against Southampton, the corrosive tentacles of complacency gripped certain City players, noted mainly in the lapses of concentration and positional discipline with led to both of the visitors' goals.
For the first goal, there were five defenders surrounding Rickie Lambert, yet he still had a two-metre circle of space inside the opposition penalty area to get that shot on goal and find the back of the net.
Every City player involved in that situation was watching the ball instead of closing down the away team's options.
And for the second goal which put the Saints 2-1 up, most of the City players were camped so far in the opponent's final third that when they broke on the counter-attack, Southampton had five players in attack compared to City's three in defence.
Clearly for the first goal, the City defenders didn't expect the likes of Lambert to be such good finishers, while for the second, they underestimated the ability of the Saints on the counter.
It was the classic case of complacency that plagued Manchester United last season—if they're not careful, Manchester City could suffer the same fate this term.
It appears Manchester City manager Roberto Mancini has tried to model FC Barcelona in terms of the positioning of his fullbacks.
Pablo Zabaleta and Gael Clichy both spent big chunks of the game high up the wing and virtually in line with David Silva, allowing the creative players, i.e. Silva and Samir Nasri, to move inside and dictate play at the core of the opposition defence.
This effectively created a midfield five, with Jack Rodwell staying deep and covering defence.
When City have possession, it's a great tactic which gives them a plethora of passing options across the midfield, which, in turn, makes the opposition chase the game more, stretches their shape and creates pockets of space in the final third for Silva, Nasri, Sergio Aguero and Carlos Tevez to exploit.
But when they lose the ball, Mancini's men have yet to come to terms with how quick every Premier League team is capable of counter-attacking.
For the second goal City conceded, the super-advanced positions of Clichy and Zabaleta cost them dearly, with the lack of cover at the back allowing Steven Davis the time to exploit space in City's penalty area and finish with aplomb.
The high-line fullbacks work well in attack, but unless City can get enough cover to cope with counter-attacks, better teams than Southampton will punish the Champions nine ways to Sunday.
Jack Rodwell would have learnt against Southampton that you can't switch off for a second in the Premier League, especially if you're playing for the Champions.
He was directly responsible for the goal that put the away side 2-1 up, with his sloppy uncalculated pass affording the Saints a golden opportunity for an incredibly effective counter-attack.
When playing the ball around in the final third, players need to be aware of who's covering defensively and how many opponents are primed to break and hit their team on the counter.
It's something every other player for City was clearly aware of, but for poor Jack Rodwell, he failed to think before hitting that pass.
Had that Saints goal been the winner, it would've been Rodwell's inexperience that would've cost City the match.
Besides that mistake he held his own, he put in a great first-half tackle to prevent a potential goal. But overall, his lack of pedigree and experience compared to his teammates led to a very conservative style of play, which meant he had very little influence on the match.
He did have a great pass success rate of 96 percent from an impressive 93 passes (89 completed) (h/t WhoScored?com), but a significant chunk of those were either sideways or backwards.
His inexperience led to his team conceding, while going forward, he contributed nothing, as he made no risqué moves, hitting zero key passes (chances created).
Chances are, Gareth Barry or Nigel De Jong wouldn't have made the same costly, goal-conceding mistake, while Barry averaged at least one key pass per game last season.
If City are to start with Jack Rodwell in future matches, they need to play him in matches they can afford to lose, unless he starts learning quickly.
And Silva did not have his finishing boots on against the Saints, with the 26-year-old playmaker missing another gilt-edged chance, as he hit just one shot on target from four attempted.
Yaya Toure, Carlos Tevez and Samir Nasri also missed golden opportunities, as overall, City hit just eight shots on target from a whopping total of 23 shots—at a rate of just 35 percent on target.
Of course, City weren't helped by the injury to Sergio Aguero, and having that many shots shows the creativity is there in the Citizens midfield.
Nonetheless, it's that lack of goalscoring conviction which became another fatal flaw for Manchester United last season, with their complacency and poor shots-to-goals ratio a deleterious part of their unsuccessful title defence.
As it stands, City have such that hamartia and will need to rectify their finishing problem soon if they are to build that all-important winning momentum.
Sergio Aguero suffered a painful knee injury after just six minutes in the match against Southampton and could be out for the rest of the month, at least.
Manchester City boss Roberto Mancini said of the injury (h/t Daily Mail):
We need to wait and, while I hope it is not serious, it is a worry. It is important luck is on your side over the course of a season, but we have been unfortunate with this injury. The knee is always dangerous.
Maybe he is out for a week, or three or four weeks, or until after the international break. We have to see.
The news is a big concern for Mancini and his City team, not least of all because of his understanding with Carlos Tevez.
Tevez is finally back on form, having looked a lot sharper than last season, with City reaping the rewards greatly.
However, much of his fine form is down to his understanding with Aguero, with the understanding and knowledge of each others' movements, general style and passing in the final third key to their success.
Without Aguero, not only will City be robbed off their most talented attacking threat, but the form of Tevez could also dip again.
Considering momentum is key to Tevez scoring goals—with the 28-year-old Argentine, like Wayne Rooney at United, a player who needs a few games finds form and scores prolifically but inconsistently—the Aguero injury might also rob City of Tevez's full attacking threat, especially seeing as he doesn't have the same understanding with Edin Dzeko or Mario Balotelli.
So overall, with Aguero out and Tevez's form subsequently at risk of dipping markedly—which fails to aid the significant concern of poor finishing—the injury suffered by the 24-year-old Argentine is possibly Manchester City's biggest reason for concern despite the 3-2 win against Southampton.