While Aguero wasn’t his usual self playing as a left sided forward, substituting the Argentine and bringing on a full back by trade looked like a crazy decision with the game scoreless and rivals Manchester United a goal to the good at home to West Ham.
As if that wasn’t enough, the move also coincided with a shift to the much maligned three at the back system which has come in for plenty of criticism when used so far this season.
Within a minute of the change however, City took the lead as Mario Balotelli pounced on a spillage by Ali Al Habsi to score his first league goal of the season at the second attempt.
Just two minutes later another substitute, James Milner, doubled the lead with a piledriver into the top corner from outside the box.
The first hour of the game was poor to say the least as, yet again, Yaya Toure struggled to have an impact while Balotelli and Aguero were well marshalled by the Wigan defence.
So what changed after 60 minutes?
Well firstly James Milner took the place of Javi Garcia, who had a very poor night and looked well off the pace.
Milner, by contrast, was instantly more industrious and mobile, leaving Gareth Barry as the sole protective shield in front of a back four which was rarely troubled by Wigan’s attack.
Secondly, and more importantly, Mancini tweaked the shape of the team once Kolarov came on, with Pablo Zabaleta, Vincent Kompany and Matija Nastasic making up the defensive trio.
Interestingly, all three of those players completed 93% or more of their passes (Zabaleta was 52/52) while long balls were kept very much to a minimum, and this ability to retain possession when playing out from the back was a factor in restricting Wigan to just one shot on target (five off).
The switch in formation also enabled David Silva to move infield, and it was from a central position that he had a hand in Milner’s goal.
Gareth Barry was another strong performed; it was his shot which Al Habsi fluffed for Balotelli’s opener, while he also laid on the pass for Milner’s long range effort and barely put a foot wrong throughout.
The decision to go with a back three for the last third of the game also paid dividends when used against Tottenham at home a few weeks back.
With City a goal down, Mancini introduced Maicon as a substitute for Nastasic in a move that turned the game in his side’s favour as goals from Aguero and Edin Dzeko gave them the three points.
While it may be a viable Plan B, it hasn’t proved to be very successful when used from the outset, with last week’s first 20 minutes against Real Madrid in the Champions League reinforcing that.
The Spanish side could have been three or four up as Cristiano Ronaldo, Angel Di Maria and Karim Benzema enjoyed the freedom of the Etihad, and it was only when Mancini reverted to a more orthodox back four that City stemmed the flow and got a foothold in the game.
Ultimately the jury is still out on Mancini’s tinkering, but it has shown that he not as stubborn and set in his ways as was made out in his early days in charge when he was labelled boring and “Typically Italian” for building from the back and using two holding midfielders week in, week out.
The win over Wigan makes City the first team in Premier League history to remain unbeaten after the first 14 games of successive seasons, though this weekend’s clash with Everton at home will provide a very stern test.
The Toffees were the last side to win at the Etihad Stadium in the league back in December 2010, and City fans have long seen this fixture as a potential banana skin.
With Manchester United travelling to Reading on Saturday for a game they are expected to win, three points for City will keep it nice and tight at the top ahead of the first Derby of the season on December 9.