Atletico lost the second-leg of their semifinal 3-0, but won the tie 4-3 on aggregate.
Simeone smiled afterwards: "I'd go back to the first match where we had a great first half. In the second half, we held off their attacks. I left that day angry because we could have scored another goal. Because I know what these players are capable of.
"Today, Pedri and Raphniha were back, they bring a different rhythm, they're extraordinary. It hurts that the goals came more from a lack of focus on set pieces. It led us to a difficult moment.
"I loved (Jose) Giménez, he brought maturity to the team. We couldn't play the way we wanted. We secured a crucial victory for our fans; we needed a final."
Atletico are back in the Copa final after thirteen years.
Simeone continued: "We had reached two semifinals, this was our third, we were close. Our opponents then were superior. In this two-legged tie, we were better than Barcelona.
"Today we were superior, but we couldn't control set pieces. If they play well and then score goals, it's even more difficult."
The Argentine added, "We planned the game to attack, but it didn't happen, or it happened very rarely. Anything you imagine can happen, or it can't. Extremely high intensity; (Alejandro) Balde and (Jules) Kounde had to come off.
"To compete at the highest levels, you have to play like this."