The Andalusians side overcame a 1-0 first-leg deficit to beat Porto while the Bundesliga champions beat Shakhtar Donetsk to reach the last eight, and the 31-year-old admits it is hard to focus on domestic matters.
“We're already dreaming," he told AS. "We know we have two important games in the league before the Champions League tie.
“It's hard. You go into the game, after the match with Valladolid, knowing you have the most important game of your life."
Isco and Roque Santa Cruz struck the goals at El Madrigal to send the Andalusians through to the last eight, and Joaquin confessed the feeling following the victory was indescribable.
“People on the street are talking about it," he continued. "The buzz fills you with a sense of responsibility, but also the desire to do something historic for those people who would be there.
"To explain it in words is difficult because it was a magical night.”
The former Valencia player added that he has been impressed by what he has seen of the German double winners this season, voicing a particular admiration for attacking counterpart Marco Reus.
“Yes, I have seen them play in some German league games. They are team that presses and they play good football. There is one young player, Reus, that I like," he added.