Barca go to Atletico tonight for the first-leg of the tie.
Asked about Real Madrid being knocked out by Albacete, before Barca beat the Segunda club in the quarterfinal, Flick shrugged: "Talking about Real Madrid doesn't help me.
"It seemed like the right response because we have to respect the teams in the Segunda and Tercera Divisions, who have had a fantastic Cup run.
"Last year we had Barbastro, Betis, and Valencia... It's about respecting our opponents. They qualified, they have the quality, and they've shown they can beat First Division teams. That's all it is.
"I only have to focus on my club, my team, my fans, and that's all that matters to me; the rest is a waste of energy."
Then quizzed if he felt Barca have had a comfortable Copa run, Flick added: "Yeah? Just ask Real Madrid..."