Real Madrid slipped to a shock defeat to Real Betis at the Santiago Bernabeu on Wednesday night, with Antonio Sanabria scoring in stoppage time to secure a 1-0 win for the visitors.
The result leaves Zinedine Zidane's side seven points behind leaders Barcelona after five games played.
Elsewhere, Sevilla beat Las Palmas to move back into second place, while Atletico Madrid won at Athletic Bilbao and lie third on 11 points.
Athletic Bilbao 1-2 Atletico Madrid
Leganes 0-0 Girona
Deportivo La Coruna 1-0 Alaves
Real Madrid 0-1 Real Betis
Sevilla 1-0 Las Palmas
La Liga Table (Goal Difference)
1. Barcelona 15 (+15)
2. Sevilla 13 (+6)
3. Atletico Madrid 11 (+6)
4. Valencia 9 (+6)
5. Real Sociedad 9 (+4)
6. Real Betis 9 (-1)
7. Real Madrid 8 (+4)
8. Athletic Bilbao 7 (+2)
9. Leganes 7 (0)
10. Villarreal 6 (+1)
11. Levante 6 (+1)
12. Las Palmas 6 (-2)
13. Eibar 6 (-7)
14. Girona 5 (-2)
15. Getafe 4 (-1)
16. Deportivo 4 (-5)
17. Espanyol 4 (-5)
18. Celta Vigo 3 (-2)
19. Alaves 0 (-8)
20. Malaga 0 (-10)
Real Madrid found it tough going against Real Betis, with the hosts unable to score in the first half of a La Liga match for the first time since April, per Opta:
0 - Real Madrid have failed to score in a first half of a La Liga game for the first time since April against Atletico (1-1). Maze. https://t.co/giqKGI7Jnd2017-9-20 20:54:44
Los Blancos had plenty of chances and were unlucky not to go ahead after the break through Dani Carvajal, as noted by Dermot Corrigan of ESPN FC:
Dermot Corrigan @dermotmcorrigan
Carvajal hits post on the stretch from tight angle, from Ronaldo cross.2017-9-20 21:13:50
Betis continued to ride their luck, with Gareth Bale the next Madrid player to be denied by the woodwork with what would have been a special goal, per football writer Sid Lowe:
Sid Lowe @sidlowe
Bale off post! Would have been a ridiculously good goal. Backheel volley through legs.2017-9-20 21:32:46
The evening then almost got even worse for Madrid, with Betis managing to get the ball in the back of the net, only for it to be ruled out for offside.
Betis were not to be denied for too long, though, and Sanabria headed a great cross past Keylor Navas in the fourth minute of injury time to stun the home crowd.
ESPN FC's Michael Cox neatly summarised the game, in one of the most surprising results of the Liga season so far:
Michael Cox @Zonal_Marking
Wow, incredible late smash-and-grab from Betis at the Bernabeu. Sensational second half.2017-9-20 21:52:15
The match was also notable for being the end of Madrid's run of scoring in consecutive matches, as noted by Marca's Chris Winterburn:
Chris Winterburn @cmwinterburn
Real Madrid's run of consecutive scoring matches comes to an end at 73.2017-9-20 21:55:47
Meanwhile, Atletico Madrid moved to within four points of leaders Barcelona with a 2-1 win over Athletic Bilbao at San Mames.
The visitors hit the post just after the half-hour mark through Nico Gaitan but could have gone behind on 38 minutes when Filipe Luis was adjudged to have fouled Raul Garcia and conceded a penalty.
Up stepped Aritz Aduriz, but he could not beat goalkeeper Jan Oblak who dived to his left to keep it out.
Opta highlighted just how good the Slovenia international is when it comes to spot-kicks:
60% - Jan Oblak has saved six of the 10 penalties he has faced in all competitions for Atletico (excluding penalty shootouts). Guardian. https://t.co/ezrEjTnF4V2017-9-20 18:51:27
Atletico took the lead 10 minutes into the second half, with Koke and Antoine Griezmann swapping passes before finding Angel Correa who swept the ball home
The visitors then doubled their advantage in the 73rd minute with Griezmann again involved. His brilliant pass found Yannick Carrasco, who smashed the ball past goalkeeper Kepa Arrizabalaga.
Garcia managed to pull one back in stoppage time, but it was just a consolation as Atletico secured an impressive win, as noted by football writer Kieran Canning:
Kieran Canning @KieranCanning
Atletico heading for a very impressive win in Bilbao. Carrasco with the second after lovely Correa opener. Griezmann key in both too2017-9-20 19:31:07
Sevilla also picked up all three points in a 1-0 home win over Las Palmas but left it late to claim the victory.
The hosts looked to be heading for a draw until Jesus Navas popped up in the 82nd minute with a cross that beat goalkeeper Leandro Chichizola and crept in off the crossbar.
It was a fitting way for Navas to mark his 400th Sevilla appearance, as celebrated by the club's official Twitter account:
Sevilla FC @SevillaFC_ENG
83' | GOOOOOOOOOOOOOOAAAAAAAL!!! @JNavas on his 400th #SevillaFC appearance!!! #SevillaFC 1-0 @UDLP_Oficial #vamosmisevilla2017-9-20 21:40:33
The only other Liga game of the night saw Deportivo pick up their first win of the season by beating Alaves 1-0 at home. The result means the visitors are still without a point or even a goal after five matches.