Real Madrid continued their disastrous start to the La Liga campaign with a 1-0 home loss against Real Betis on Wednesday.
Cristiano Ronaldo made his long-awaited comeback after completing a five-match ban for shoving a referee, but couldn't provide the breakthrough Los Blancos required as Zinedine Zidane's men suffered their first defeat from five opening league fixtures.
Gareth Bale nearly fired the home side ahead late, with a sensational back-heel of Lucas Vazquez's cross from the right, but Betis keeper Antonio Adan did enough to parry his low shot off the crossbar to keep the scoreline level.
Betis thought they'd snatched a late winner in the 90th minute, but the goal was rightfully ruled offside, much to the visitors' dismay.
But they were celebrating four minutes later, when Antonio Sanabria headed home Antonio Barragan's inch-perfect cross past a helpless Keylor Navas from close range.
The defending champions have now taken just eight points from five matches on the young season. They are seven points behind leaders Barcelona, who throttled Eibar 6-1 on Tuesday.
Angel Correa and Yannick Carrasco scored second-half goals as Atletico Madrid extended their unbeaten league start to five matches with a 2-1 win at Athletic Bilbao.
Atletico, unbeaten in six games in all competitions this season, broke the deadlock through Correa 10 minutes into the second half and Carrasco added a second in the 73rd minute.
Bilbao, who slipped to a first home defeat of the season, squandered a first-half penalty when Aritz Aduriz's spot kick, for Filipe Luis' foul on Raul Garcia, was saved by Jan Oblak.
Bilbao midfielder Garcia struck a late consolation for the Basque side in the second minute of time added on.
Former Manchester City winger Jesus Navas fired the only goal as second-placed Sevilla closed the gap on Barcelona to two points after a 1-0 home win against Las Palmas.
Navas lashed home a shot into the top corner from outside the penalty area and from a tight angle in the 83rd minute as Sevilla extended their unbeaten start to the season to eight games in all competitions.
Portuguese defender Luisinho's solitary goal clinched Deportivo La Coruna a 1-0 home win against fellow strugglers Alaves.
Luisinho fired home in first-half stoppage time to secure Deportivo their first league win of the season and lift them out of the bottom three.
Deportivo goalkeeper Costel Pantilimon denied Alaves an equaliser early in the second half when he saved winger Burgui's angled drive in the bottom corner.
Alaves, who stay second from bottom, and Malaga have both lost their first five league games.
And finally, Leganes drew 0-0 at home against Girona, but were grateful for the woodwork in the 73rd minute when visiting defender Juanpe's header hit the crossbar.
Information from Press Association Sport was used in this report.