Mancini’s men remained on the front foot in the second period and Emmerson Boyce had to produce a timely block to prevent Sergio Aguero from turning in Tevez’s low cross at the near post.
Mancini introduced James Milner and Jack Rodwell from the bench, and the pair nearly combined for the opener in the 72nd minute when Rodwell got his head to Milner’s free-kick, only for Robles to save.
The Latics had been subdued, but with 15 minutes to play Maloney almost broke the deadlock with a cunning free-kick from wide on the right that bounced off the top of the bar.
Wigan were given further reason for optimism in the 84th minute, when Pablo Zabaleta was shown a second yellow card for felling McManaman as he bore down on goal.
Maloney whipped the resulting free-kick wide, but Wigan had the momentum and in the first minute of stoppage-time Watson glanced Maloney’s corner past Hart to write his name in FA Cup final history.