Even Chelsea at that time cannot be compared to Manchester in any way, both historically and currently, and it got worse when Chelsea started to struggle. Even with magic there is no way Chelseawould have won, and Manchester City did not even use their entire roster to play; instead, they played without any pressure. Manchester City did not emphasize that they were the upcoming champions. We all know the Champions already, since arsenal almost tasted glory they will definitely do well next season and buy more players.
Why will you even compare Manchester city with Chelsea, Manchester City can't risk using their main squad to play against Chelsea when they know the match is really useless to them, the remaining matches they are having in Premier League they won't use their main players, they are scared of losing their main player's to injury, since they have already win the Premier League even if they lose the remaining matches left, they have to reserve their main squad to play against inter Milan in champions league, Manchester City will try their possible best to win inter Milan, they will want to win both the premier league and champions league.