Manuel Pellegrini's side have won all six of their home league matches so far this season and have scored 41 goals in 10 competitive fixtures at the Etihad Stadium.
"I think City away is the biggest challenge for anyone in this league with the way they play," Sky Sports News quotes him as saying. "They're expansive and they look like one of Pellegrini's teams so I think it's a difficult game for us.
"Spurs were under par against them last week, but with the players they've got like [Sergio] Aguero, Edin Dzeko and [Alvaro] Negredo, they've got four or five front players who would get in any team in the Premier League.
"They're playing really well. Pellegrini's teams are all or nothing, and at the moment it's the former. They're getting goals and even if they concede a couple they're likely to outscore you, but we'll concentrate on ourselves."
Swansea are currently 10th in the league table, while City are fourth.