Manchester City were one of the favourites to win the competition on their way to potentially completing the quadruple – FA Cup, EFL Cup, Premier League and Champions League
Will Grigg scored the only goal of the game to send the Latics into the quarter-finals.
After the final whistle, Guardiola told BBC Sport: “Congratulations for Wigan for the qualification. We did absolutely everything, we made a mistake and this kind of game is like a final. OK, we accept the defeat. Congratulations to the winner.
“It was like a final. They had one shot on target, I don’t have regrets with the way we played, the performance, the heart. I judge my players on intentions and not results and the intentions were good. Wigan won, congratulations to them and now we rest to prepare for the EFL Cup final.”