Los Colchoneros had been on an unbeaten run of 18 league games, having only lost to Celta de Vigo in match day three of LaLiga, but were forced to return to Madrid without any points after succumbing to a 1-0 defeat.
Sergio Canales scored the only goal of the game in the 65th minute, seeing him convert from the penalty spot after defender Felipe Luis handled the ball in the area.
In that game, there was one very familiar face that Juventini know all too well, and that is Alvaro Morata, who made his debut against Betis and featured for the full 90 minutes. The Spanish striker is Diego Simeone's most recent signing, having completed his loan switch from Chelsea until the end of the season.
Atletico will return to action on Saturday, February 9, where they will take on cross-town rivals Real Madrid in the Madrid Derby. The defeat to Betis means they are six points adrift of league leaders, Barcelona.