Atletico Madrid's 100 per cent LaLiga record was emphatically ended on Saturday, as they lost 2-0 to a fired-up Real Sociedad in the first competitive fixture played at the Reale Arena.
Diego Simeone's side had managed three straight wins prior to the international break but turned in a below-par performance on the road, conceding two goals in a costly three-minute spell in the second half.
After a trio of away games at the start of the 2019-20 campaign, Sociedad excelled in front of a raucous crowd at their revamped home, albeit Martin Odegaard's opener owed much to a huge deflection off Stefan Savic.
They doubled their lead soon after through debutant Nacho Monreal, the former Arsenal defender seizing on a loose ball to poke home ahead of Jan Oblak.
Atletico's goalkeeper was injured in trying to prevent Monreal scoring and, after lengthy treatment on the field, was replaced by Antonio Adan, adding further to Simeone's concerns ahead of the start of the Champions League group stage in midweek.