An own goal from Bradley Johnson set them on their way before David Silva, Matija Nastasic, Alvaro Negredo, Yaya Toure, Sergio Aguero and Edin Dzeko all got on the scoresheet.
It was City's biggest top-flight victory since 1968 and their most emphatic at any level since hammering Huddersfield 10-1 in the old Second Division in 1987.
Manuel Pellegrini: "It was a really good performance.
"The team played really well during the 90 minutes, not only the first half.
"Normally when winning 4-0 at half-time, in the second half a team finish or stop.
"But the team continued playing exactly the same and that's very important for me.
"It is so important for me to see the way I want them to play.
"They are very good technical players when they move the ball quick and move into space, it is very difficult for our team not to score so we must continue the same way.
"My duty is to see, every week, which are the best players to play every game. We have a lot of games.
"This game, I thought Joe Hart needed a rest. I think it will be useful for him.
"He has played every match for the last two and a half years here.
"We will work hard behind Joe so he can return to his normal performance level as soon as possible but (against Norwich) I thought the best goalkeeper was Pantilimon, nothing more."