Real Madrid won the first-leg of their round of 16 tie 3-0 on Wednesday night, with Fede Valverde hitting a hat-trick.
"Right now, not much,” Guardiola said when asked about City’s chances of fighting back in the tie. “Of course we’re going to try and it is difficult right now.
“But we will be there with our people and we will do better to be more active in the final third and we will try."
City goalkeeper Gigio Donnarumma denied Vinicius Junior from the penalty spot and Guardiola continued: “3-0 is better than four, we cannot deny that.
“It’s difficult sometimes to control transitions when we lose the ball and they connect, they don’t put the ball away and then players like Vinicius can run.
“I had the feeling that it was quite decent and well played.
“We arrived, I don’t know how many times, to the byline. Individual actions from Jeremy (Doku), long balls in the second half especially for Antoine (Semenyo) and Nico (O’Reilly) then passes in the six-yard box we were not able to (beat Thibaut) Courtois.
“We miss that action in the first 50 minutes. The first goal was not well defended and then after that the quality they have."
He added, “I think we’ve tried to do our best but we didn’t create chances where Courtois had to intervene.
“We got into the box many times - when you are able to do that it means you have followed a good process.
“They are always very dangerous but I don’t have the feeling that Courtois has played a great game.
“We reached that line many times but we were just missing this detail.”