Guardiola also singled Phil Foden out for praise after the 18-year-old's impressive performance against the Blues.
"It was so hard but the players played really well," Guardiola told BBC Sport. "Our mentality was right and we got the win.
"We prepare game by game. Our results will determine who we are. We will see at the end of the season what our level is.
"Phil Foden is ready for the Premier League, he was last season and now he has one more year experience. It's so good for us."
Man City open their league campaign with a trip to Arsenal next Sunday.