The three matches that I think are difficult to predict are:
Real Madrid versus Atletico
Bayern Munich versus Leverkusen
I actually don't really like the results of this draw. These two knockout phase matches seem to be like a domestic league. Spanish league and Bundesliga. Indeed, Spain still has 1 other representative equal to the Bundesliga. As a Real Madrid fan, I don't like it because they always have difficulties when they meet Atletico. This makes me worried if they lose.
Then Bayern too, they are difficult against Leverkusen. But indeed this condition is in the League, and I always see a difference in spirit when I am in the UCL. Another surprise was also for Aston Villa and Bruges, they were able to take advantage of opportunities with a new system until the knockout phase. But indeed the two have to compete.
PSG versus Liverpool
I am more confident in Liverpool to qualify for the next phase, they are very strong in the League and UCL