The Sky Blues are down 1-0 to Tottenham after the first leg of their quarterfinal tie.
The two Premier League clubs will meet at the Etihad on Wednesday, and Guardiola is confident his team will secure a victory.
He told Sky Sports News: "The only [reason to] panic is that you will be out of the competition. I'm pretty sure we're going to be in the next Champions League.
"We'll be sad one day, two days [if we lose the quarter-final], then after we play for the Premier League and the chance to be champion. We play the final of the FA Cup, and next season we'll be there again; that is for sure.
"If you ask me what is going to happen, we'll be in the semi-finals; that is what I feel right now.
"It's what I felt right after the game and when I reviewed the game. Maybe I'm wrong but what I feel now, we'll be in the semi-finals."