I have for once a very good feeling before this match.
If the team manages to score the first goal or just more than 1 goal during the match then qualification for the next round (semifinal) should be beyond any doubt.
The thug Godín is suspended while Koke is out too. Thiago as well. This should be exploited.
It will be very difficult for Atlético to prevent either Messi, Neymar or Suárez from scoring when they have to chase the win from the start.
In short I don't see Atlético being able to progress unless the team somehow collapses. This Atlético team is nowhere near last season's level.
The first 30 minutes will be crucial. I expect Atlético to attack from the very beginning.