I think Atletico Madrid is too focused on the second leg match against Inter Milan in the middle of the week so they get bad results in the continued La Liga match against Cadiz, this is an unexpected result and even a big surprise when Atletico Madrid was unable to score a single goal against Cadiz. .
In the last 5 matches Atletico Madrid only won 1 win, indeed Atletico Madrid's performance is quite declining but that doesn't mean they can be underestimated in the second leg of the UCL, they are only 1 goal behind and they will play at home, of course everything the possibility is still possible for it to happen.
I think the most detrimental thing about Atletico Madrid's defeat is that their points distance from 5th place is so close now that they are not safe enough to finish in top 4 position.
Athletic Bilbao will most likely close the distance and get closer to Athletic, but this is acceptable for now, since Athletic will retain their place in the top 4. And yes, now the most important thing is to win the match with Inter, it is clear that Simione will only focus on this match, and the match with Cadiz was most likely a secondary task. If they cannot beat Inter, then everything will be over for them in the Champions League, and then they can fully concentrate on La Liga, but as long as there is a chance, Atletico will definitely fight in the Champions League.