#1 Barcelona will be playing their second game after just 60 hours with a key UCL fixture following that after a week's time

At this time of the season, a lot more factors will play a role in the outcome of the games. With fixtures coming thick and fast, teams won’t have sufficient time to recoup their full strength and fitness.
After a disappointing 1-1 draw against Las Palmas on Thursday, Barcelona will be playing their next game on Sunday, in just 60 hours after the Thursday fixture. Atletico too played a midweek game but they will have an extra 24 hours rest for the crunch Sunday fixture.
Also, it’s advantage Atletico Madrid in La Liga after their UEFA Champions League exit. FC Barcelona go into the fixture with an eye on the UEFA Champions League second-leg game against Chelsea while Diego Simeone’s side have their complete focus on the game against Barcelona.