The Atletico Madrid right-back missed the decisive spot-kick as Atletico were beaten by city rivals Real in the final of Europe's elite club competition in 2015-16.
Juanfran was subsequently reduced to tears, and penned a heartfelt letter begging the Atletico support for forgiveness.
However, he insists that he has now bounced back from the disappointment he felt at San Siro, and is eager to exorcise the demons once and for all by progressing deep into this summer's Euros in France.
"It's that I've psyched myself up for it. Physically I feel good, even better than in some stages of the season," he told Goal in an exclusive interview.
"I have prepared myself, I trust myself and trust the player I am. I knew at the time that matches would be more difficult, but things would work out good. And this is how it is going. I think I can improve on some things, and I'm going to. I'll be better from here to the end for sure."
However, despite his insistence that he has recovered from his spot-kick anguish, he is desperate to avoid a penalty shootout in the last-16 encounter with Antonio Conte's men, though he is confident Spain would win such an encounter were it to go the distance.
"Especially for the team, for us not to suffer. We want to make a great game against Italy, and try to resolve it within 90 minutes," he added. "If we then have to go to penalties, then we'll deal with it knowing that we will win and we will take them better than them.
"But there is no fear of it. If I have to take a penalty I will take it. There would be no problem. And like me, the rest of my team-mates (are the same). But it's better not to do it and suffer so much... I've had a lot of suffering with penalties this year!