Atletico won 2-0 in the first-leg of their quarterfinal thanks to goals from Julian Alvarez and Alexander Sorloth. Pau Cubarsi was sent off - via VAR - for Barca before Alvarez's opener.
Araujo said afterwards: "We tried, but it wasn't enough. We came out stronger in the second half, even with one less player.
"We had possession, but we couldn't find the net. We're disappointed with the defeat, but I think we can turn this around.
This team has the ability to come back from this. I'm convinced of it. We've done it many times. It's difficult at their ground. If anyone can do this, it's us. We're going to go after them.
"(Marcus) Rashford had a chance, we could have scored, and that would have changed the game. We tried, there's nothing to criticise the team for. I think some of our players were more tired. We need to maintain a positive mindset and believe."