Man City won a ticket to the 5th round of the tournament with a difficult victory over Salford at Etihad Stadium.
Alfie Dorrington's own goal on the visiting team's side in the sixth minute helped the home team have a strong start, but it was not until the 85th minute that Man City had their second goal thanks to a close-range finish from substitute player Marc Guehi.
Despite the four-championship gap, the trophy match at the Etihad was very tense - and Guardiola said that his team was not quick to grasp the situation to cause difficulties for the opponent.
When asked if he was satisfied with the performance, Guardiola said: "No. We did not find gaps from the opponent. The gaps we attacked always depended on the opponent's defensive position and we did not do that.
That's why the match was boring. The only good news is that we went further. That's all," Guardiola said after the match.
Guardiola made nine changes in the starting lineup compared to the victory over Fulham in the Premier League, taking advantage of the opportunity to rotate players.
With a rare week of rest before continuing the race to win the Premier League title, the Spanish coach currently plans to give his players a few days off.
However, Guardiola does not want to use fatigue as an excuse for his poor performance.
I can say that mentally, we have been exhausted, we are tired, the past two or three weeks have been difficult for many reasons. The schedule has clearly stated that there will be a match in a few days. We did not pay attention to the position of the gaps that Salford created and everything was dull, slow and not good," the Man City coach added.
A positive point for Man City is the return of English defender John Stones, who made his first appearance after more than two months of recovering from a thigh injury.
He has returned. He still needs time, he is not the John Stones we used to know, but his body language is really good in terms of pressing ability and decisiveness. The important thing is that he played all 65 minutes," Guardiola added.
Last season, Salford was defeated by Man City with a score of 0-8 in the FA Cup and they can be proud of their courageous performance.
Now, their attention is again directed towards the goal of promotion to League Two.
Coach Karl Robinson said: "Before the match, I said that this football club has progressed year by year. We have made a lot of effort backstage and we feel that today we are here with a much stronger squad, as a better club.
I hate losing but you have to accept it. I think the way we lost today is proof of the bravery of the players”.
