Watson turned home Shaun Maloney's corner to flatten 10-man City, who had Pablo Zabaleta sent off near the end.
It was a deserved triumph for the Latics, for whom Callum McManaman was outstanding, and completed a personal dream for chairman Dave Whelan, who broke his leg in the 1960 final.
- Pablo Zabaleta
- Shaun Maloney
- Callum McManaman