Over the course of 90-plus minutes, the Latics more than held their own against what were lacklustre 2012 Premier League champions. Indeed, they were deserving of their success.
Before the game, City were the favourites. They were 1-to-3 with the majority of bookmakers. In 2011, they had secured this trophy with victory over Stoke City, with relative comfort. Similar results were expected.
However, after a difficult season in which they had failed to make a mark on Europe and had surrendered their Premier League crown to Manchester United without any real resistance, City showed similar failings to those which have punctuated their current campaign.
On a day when the likes of Callum McManaman and James McCarthy seemed to thrive amongst their surroundings, their more highly thought-of opponents certainly did not.
David Silva's escapability consistently eluded him, messrs Espinoza and Scharner always too quick or too clever. Yaya Toure was unable to power through midfield, the barrier of McCarthy an ever-present roadblock which he simply could not pass. City's all-Argentine strike-force of Carlos Tevez and Sergio Aguero could barely get a look in, such was the presence of Antolin Alcaraz and Paul Scharner. Spanish 'keeper Joel made a good save from Tevez with his feet in the first period, but that apart, was there anything to overly worry Roberto Martinez?
The question which will be asked regarding City's non-performance is quite simply "why?" How come a side worth far in excess of 15 times their opponents was unable to emerge victorious? The obvious answer: Football is a game which isn't played on paper.
This was a City performance which echoed the very worst of this season, especially in the supposed biggest games, particularly in the Champions League.
If we are being hypercritical, such a performance is the very reason why Roberto Mancini's job is seemingly under pressure. And why City, despite their millions, will fail to make their mark on European football any time soon.
Bayern Munich and Borussia Dortmund have made their way to a Wembley final in two weeks time, to fight it out for the European Cup. They, as well as their vanquished opponents in the tournament's semi-finals—Barcelona and Real Madrid—are sides linked by at least one common denominator, especially in the attacking third: pace. Not merely in the physical makeups of individuals, but in respect of the collective.
For three of the sides (the aforementioned German's and Jose Mourinho's Madrid), the sheer pace at which they attack, particularly in transition, is the metaphorical chalk and cheese with regards where City are concerned. And on the other hand, whilst Barcelona look to dominate possession, their preference in the final third is to open up their opponents with breakneck speed yet with intricate passing, involving the likes of Andres Iniesta, Pedro and Lionel Messi.
The old adage is that "speed kills." It's seemingly an observation that City have failed to observe.
The amount of times that Roberto Mancini's side looked to attack their less-heralded opponents at Wembley this afternoon only to subsequently slow the play down were simply innumerable.
Be it Nasri in the left-hand channel, Silva on the right or Tevez through the centre, time and again City slowed play down and allowed Wigan to regroup.
Overloads were created with Zabaleta and Clichy on the overlap only to turn inside and ignore them. Eventually passes were forced backwards or shots from difficult angles and distances were attempted. Penetration was minimal.
The killer instinct was lacking, and in the end, they paid for it. Indeed they should have paid for it long before Ben Watson's 90th minute winner.
Open to the counter-attack from the first whistle, the two best chances both fell to McManaman, only for the young Latic to squander them. (It was reminiscent of the early-season draw at home against Borussia Dortmund, albeit against a team of far less quality.)
Additionally Roger Espinoza had a plausible penalty shot turned down by Andre Marriner, when others may well have pointed to the spot. Moreover, there were a number of occasions when a tad more composure from the likes of Espinoza and Arouna Kone would have created further opportunities.
Watson's late header from a set piece may have surprised, but it gave Wigan just reward. Scrambling in the darkness for Premier League survival they may be, but today was their day in the sun.
As for the Citizens, they got exactly what they deserved from a final which won't live long in the memory, for all but the most ardent of Wigan supporters. A trophy which they should have claimed for their own inexcusably got away. Familiar failings denied City a third major trophy in as many years.
Having emerged victorious, Roberto Martinez' side must take the plaudits. Yet, today's FA Cup final only leaves more questions than answers as to where Roberto Mancini and Manchester City go from here.