Exactly, that is quite difficult to predict. Indeed, most of the world will predict Real Madrid as the winner of the second leg, but Atletico Madrid will certainly provide a very significant fight. This is the second long-awaited opportunity, the Madrid derby in the Champions League, waiting for who is the best. Not only competing in UCL but also in La Liga.
A part of me feels Atletico Madrid will win that game. It's indeed a difficult game to predict. Real Madrid might have a one-goal advantage, but when these two are concerned one goal is not that much. Atletico Madrid is a very stubborn team that is also very good. People underrate them a lot. What Madrid has over Atletico Madrid is individual quality. If Atletico can find a way to keep Vinicius, Mbappe, Rodrygo and Bellingham quiet then Madrid won't be able to do anything. What makes this more difficult is that they have to make sure they have to do this for the whole game because the split second that they give any of these players they can create something out of it just like it was in the first leg.