Having three defenders gives them a numerical advantage in the first phase of building the action, so Atletico’s central defenders are responsible for building the team’s action (Savic, Felipe, Hermoso).
Meanwhile the midfielders who are between the lines have to find free spaces in the middle of the pitch.
The choice of this formation also means that the wing-backs do not have to help build up the action as it is their teammates who create the advantage in the midfield.
The wing-backs therefore play higher and in Simeone’s case they additionally position themselves very wide right on the lines.
Thanks to this they stretch the opponent and gain more space in the middle of the field and have a lot of space on the flanks.
DIEGO SIMEONE profile on tacticof.com