"Chelsea are an incredible team," Guardiola told BBC Sport after the game. "We knew it, but we beat them.
"It was a typical high-level game. Our back four played so good today. In the most difficult period of the game, we scored on the counter.
"We created enough chances to score more goals.
"We were controlling the game," Chelsea boss Frank Lampard told BBC Match of the Day. "We were playing some great stuff and we felt in control but you can't be absolutely in control against Manchester City.
"It was bad luck for their first goal, and absolute quality from Riyad Mahrez for the second and that changed the game.
"Maybe we were a bit slow with our movement at the back. I know we were giving them a good game but I am disappointed with the small details.
"If you look at City they are an example, and we're at the absolute start of that process. A few of our players were in the Championship last season, but we want more."