The surprise loss to the League One side means City's hopes of a quadruple are over for the season.
Guardiola said: "The hours after the game were sad, but two days later we focused on the next one. Professionals know it's part of the game when people talk about how many titles you are going to win, to be unbeatable, those kinds of things…that is unrealistic to think about. Focus on the next one and try to win the game.
"I am not so dramatic in the good moments when there are nice words about us, and I am also not so dramatic when you lose a game. It's part of the game. It's always sad because we did absolutely everything to go through but Wigan did a good job and congratulations."