Atletico pay the penalty
Atletico Madrid's La Liga title hopes suffered another serious setback as two Real Sociedad penalties inflicted a 2-0 defeat on the Champions League finalists on Saturday.
Carlos Vela opened the scoring nine minutes into the second-half before handing responsibilities from the spot to Willian Jose to seal Sociedad's third straight win 15 minutes from time.
A second league defeat in three games means Atletico remain three points behind league leaders Real Madrid, but their city rivals can extend that advantage to six when they host Leganes on Sunday.
Atletico host Real in a rematch of the Champions League final after the international break on November 19.
Diego Simeone's men had sealed their place in the last 16 of the Champions League on Tuesday with a stoppage time victory over FC Rostov, but suffered a European hangover in an insipid display lacking in energy and invention.
Sociedad dominated possession in the opening 20 minutes, but it was Atletico who had the best chance before half-time when Kevin Gameiro was played in by Yannick Carrasco.