Evans saw red at 1-0, and shortly afterwards Balotelli plundered his second. Sergio Aguero added a third, before Edin Dzeko scored twice and David Silva once in a chaotic finale.
Darren Fletcher netted a lone reply for United, who conceded six in a home league game for the first time since 1930, when Newcastle went one better in a 7-4 win.
City now lead United by five points, but the symbolism of the result resonates far beyond the Premier League table. This felt like a changing of the guard, as the noisy neighbours stormed United's back garden.