The home side started much the better and led 2-0 inside 23 minutes with goals from Radamel Falcao and Filipe Luis. Betis had chances of their own, but poor finishing meant that they trailed at the interval.
Both teams had chances in the second period, but neither could make the breakthrough with Atletico securing a two-goal lead ahead of the return leg next week.
Read how it all unfolded in Sports Mole's minute-by-minute live commentary of the action below.
ATLETICO: Courtois; Juanfran, Miranda, Godin, Luis; Gabi, Suarez, Garcia, Turan; Falcao, Costa
BETIS: Castro; Perquis, Nacho, Chica, Paulao; Benat, Perez, Vilarchao, Castro; Molina, Campbell