If we look at the Atletico Madrid - Manchester United matchup, we can say that it is going to be a very competitive matchup for sure. Because I don't see a big difference between these teams now. Maybe Atletico Madrid's form lately hasn't been better than Manchester United. But if we take their general performances into account, it is more visible that they are close to each other. If I'm to favour one of them, my choice would be Manchester United.
Not only that, this is a competition between two people, Diego Simeone and Cristiano Ronaldo. Several times Atletico Madrid's steps under Diego Simeone in the Champions League had to be stopped by the team that Cristiano Ronaldo defended, while still at Real Madrid or Juventus. Uniquely Ronaldo was able to dominate the goals scored against Atletico Madrid. Will Diego Simeone break that, or vice versa Ronaldo will add to the nightmare for the 51-year-old coach.