Also think the game looked like Araujo needed to come in as Madrid started to be effective playing direct balls to Mbappe. After Araujo came on, he cleared pretty much every long ball that got played directly on the backline.
The moves Flick made been spot on. Fermin and Gavi to add more intensity in midfield to counter Madrid's superiority there for the first 30 mins in the 2nd half, and Araujo to counter their attempt to bypass midfield by playing directly on him.
Could have been a bit too late, but Ferran's goal came just at the right time to get us back in it. After Ferran's goal, Barca came back and had the clearer chances to score. Madrid taking out Vinicius also helped no doubt as Mbappe got more isolated.
That's the role of Araujo in this team basically. If for some reason midfield is not as effective at building from the back, bring him on to mark the opponent's biggest threats. He has height, intensity, and good speed. As building from the back is not the main priority anymore, and the team transitions to a pure counter attack game mostly, his on the ball problems are no longer that costly.