With both Atletico and Barcelona improving and dropping so far, the reality is that they still have a chance of finishing in the top four, so if it was just about overtaking it would be fine if they could finish in the top four in the end.
Sure, both Atletico dan Barcelona still have an opportunity to be back at the top four on the table. Point gaps among the teams in 4th-8th aren't quite small, their positions can be changed in 1 or 2 matches only. I am not surprised if Atletico or Barcelona suddenly is in the top four again in the next month (January). I assume Rayo Vallecano will be out of the top four soon because they may lose points against Atletico, Barcelona, and Real Betis in January. It is a real chance for Atletico dan Barcelona to be back at the UCL zone.