After a 4–0 away defeat to Bayern Munich and many injuries to key players in November 2020, Simeone modified the formation of his squad by introducing a three-man defence for the first time in his tenure coaching Atlético. In this formation, Carrasco played as a wing-back, with left centre-back Mario Hermoso being instructed to also cover the left-back position when Carrasco moved forward, which made the formation tactically-flexible between a three-man and four-man defence. After the formational change, Atlético were solidified defensively and began a streak of victories, including a 1–0 home victory against Barcelona. This streak propelled the team to a 10-point lead over Real Madrid and Barcelona in the 2020–21 La Liga title race by February. However, a series of bad results from February to April meant that Atlético were eliminated from the Champions League by Chelsea and Real Madrid closed the league gap to two points before the final matchday, meaning Atlético needed a victory in the last La Liga round to win the championship. Thanks to a Suárez goal in the 67th minute, Atlético Madrid managed eventually to win their second La Liga title under Simeone, after a 2–1 away win over Real Valladolid on the final match day.