Manchester City looked to get off to a pretty tame start after some extreme patience on both sides, but the game didn't take long to burst into life, City putting Wigan under an early spell of pressure which culminated in a close effort, Yaya Toure getting the rebound after Carlos Tevez's free-kick struck the wall, but Joel Robles was alert to tip his snapped effort around the post.
It was then Wigan who mounted most of the attacks, with the trio of Shaun Maloney, Arouna Kone and Callum McManaman looking dangerous on the counter-attack. The three combined for a breakaway chance when Kone found the young winger, and after getting down the right channel for a clear chance, he made the decision to cut back on his left foot to send in an effort which curled just wide of the post.
The match soon developed into an end-to-end affair, and after Maloney saw an acrobatic volley from Roger Espinoza's deflected cross, Sergio Aguero was inches away from getting enough contact on David Silva's through-ball to divert it into the net. Both sides were playing fluently, although with City noticably a gear or two below their top level.
After a brief lull, City had their best chance of the game. Silva's ball to Carlos Tevez ended up wrong-footing Joel Robles, but the Argentinian couldn't find the net despite the keeper committing himself, with the ball striking Robles' trailing leg to bounce over the bar.
City then had a slice of fortune themselves after Espinoza escaped down the left channel to threaten the City goal, before falling under the challenge of Pablo Zabaleta. Andre Marriner waved play on, although replays showed the Honduran had more than a case for the penalty. Just afterwards, Wigan could've put themselves in the lead anyway - Callum McManaman with some unlikely shades of Jay-Jay Okocha vs. Oliver Kahn after he burst clear of Zabaleta, rounded Joe Hart, but was forced to cut back into the area and take on two more players before having his eventual effort blocked.
After the second half got underway, City looked predictably more determined after a somewhat sluggish display in the opening forty-five minutes, and they created the first chance, Carlos Tevez making mincemeat of Paul Scharner before sending in a near-post cross for Aguero. Fortunately for Wigan, Emerson Boyce had tracked his run perfectly to make a block and deny the striker.
After what appeared to be a lull, Manchester City had a penalty shout courtesy of Paul Scharner as he hauled down Aguero in the area as the striker attempted - in vain regardless of Scharner's intervention to get onto the end of a pass from David Silva. Perhaps deciding that it was a lost cause, Marriner once again chose to show leniency and deny a spot-kick, and the game remained deadlocked.
Wigan were soon on the attack themselves as the game jerked back into life. The dangerous McManaman wasn't done after his two close efforts in the first half - after one run at Gael Clichy eventually saw the ball hacked clear, it was soon snapped up by McArthur, who found him again - this time he took his run inside, before darting back into the channel between Vincent Kompany and Clichy, but the Belgian recovered to deflect his effort away with a crucial last-ditch challenge.
Roberto Mancini then made the curious decision to replace Carlos Tevez with Jack Rodwell, and the former Everton man didn't have to wait long for a chance, getting on the end of a City free-kick in a dangerous area but sending his header too close to Robles.
Continuing the end-to-end theme, Wigan then enjoyed some pressure, with McManaman continuing to have Clichy on toast down the right flank. One cross was just overhit for Arouna Kone, before the winger then won a free-kick after being brought down by Nastasic.
Yet perhaps McManaman's most telling contribution was to come shortly afterwards when, after bursting through with a chance of getting clear on goal, he was felled by a brutal tackle from Pablo Zabaleta, who picked up a second yellow card to deal his side a huge blow and set up the prospect of City having to play extra time with a man disadvantage.
McManaman was yet again involved as Wigan felt they had a penalty when he burst past Clichy down the byline and appeared to be shoved over by Clichy. Marriner once more waved for a corner, but it didn't matter - Maloney sent in the resultant corner for the substitute Ben Watson to get past Rodwell and plant a towering header right into the top corner and send the Wigan fans into ecstasy.
WIth injury time already in progress, City poured forwards in search of an equaliser, and the Wigan defence needed to be alert to block Aguero's effort after Edin Dzeko flicked on a hopeful long ball, but that proved to be the last action of the game. Wigan were triumphant, pulling off one of the greatest FA Cup shocks of all time.