Ben Watson scored on a header off Shaun Maloney’s corner kick in the 90th minute at Wembley Stadium.
“The boys were fantastic and they deserve it,” Watson told the BBC. “To come on and score the winner in the FA Cup final is a dream.”
Wigan, based near Manchester, put together its roster for less than $30 million, while City’s cost more than 10 times than amount.
But season still could end on a low for Wigan, which is 18th in the Premier League at 9-19-8 with two games left. Wigan faces relegation to the second-tier League Championship next season unless it can climb in the standings.
“It’s unbelievable. It’s some achievement for everyone in the club,” Wigan midfielder James McCarthy said. “Now it’s down to the league. It’s a massive week for the club. We have to put on a massive show for the rest of the season.”
Wigan was led out onto the field by chairman Dave Whelan, whose playing career ended at old Wembley stadium when he broke a leg while playing for Blackburn in the 1960 final.
For City, the loss could intensify the turmoil threatening to engulf the club as it wasted the last chance to end the season with a trophy. The team has not denied a report that Malaga’s Manuel Pellegrini has been approached to replace Roberto Mancini as manager.
Mancini helped end a 35-year trophy drought when City won the 2011 FA Cup, and the club won the Premier League last year.
City fans made their feeling clear toward the club’s Abu Dhabi hierarchy, chanting in support of Mancini from the start and bellowing abuse about Pellegrini.