Ten-man Real Madrid crashed to a 1-0 defeat at modest Levante on Sunday, a morale-sapping setback coming just 24 hours after bitter rivals Barcelona had staged an eight-goal masterclass against Osasuna.
Real rested Cristiano Ronaldo and Mesut Ozil as they looked to maintain their 100 percent record and keep pace with leaders Valencia who beat Sporting Gijon 1-0 to keep up their own perfect start.
But the defeat left Jose Mourinho's side in fourth spot, three points behind Valencia and one back from Barcelona.
Real had plenty of possession but Levante defended resolutely.
Kaka missed an early chance and Karim Benzema was a danger but Real's task became a lot harder following the dismissal of Sami Khedira for a second yellow card.
Ronaldo was brought on after the break but Real still were unable to create clear-cut chances and instead they were caught on the break through Arouna Kone who grabbed the only goal in the 68th minute.
On Saturday, Lionel Messi grabbed a hat-trick as Barcelona responded emphatically to questions over their motivation by demolishing Osasuna.
David Villa (2), Cesc Fabregas and Xavi were also on target, while the unfortunate Roversio scored an own-goal, as the Spanish and European champions rebounded from two successive draws.
Barca coach Pep Guardiola denied there was ever a problem inside the dressing room and insisted he was never worried by criticism that his side had become complacent with success.
"I wasn't angry, people said I was angry but it wasn't the case. Obviously there is a part of the media which wants Barcelona to do badly and likewise there is a section which wants Real Madrid to do so," he said after the game.
"I am not angry because my players haven't given me a reason to be so. I defend my players and my job is to convince them that they can win every game. If one day I think my players haven't worked hard enough I will say it."
A poacher's goal from in-form Roberto Soldado gave Valencia victory over Sporting Gijon while Radamel Falcao fired a hat-trick as he led Atletico Madrid to a 4-0 victory over Racing Santander.
New signings Falcao and Diego were combining well, and the Colombian started the rout slotting home clinically after 23 minutes. He then sent the keeper the wrong way with a penalty before half-time and completed his hat-trick ten minutes into the second half.
Substitute Adrian Lopez scored 12 minutes from the end for a resounding win.
Luis Garcia hit both goals, including a last-minute winner, as he helped Zaragoza to a 2-1 victory over his former club Espanyol.
The visitors' Javi Lopez equalised Garcia's opener and the match appeared to be heading for a draw until Zaragoza won a penalty three minutes from time.
Garcia saw his spot-kicked blocked by 'keeper Cristian Alvarez but there was still time for him to make amends and score the winner in injury time.
An early Michu header gave Rayo Vallecano a 1-0 Madrid derby victory at Getafe in Sunday's early game.
It was the first time that the two lesser lights of the Spanish capital had met in the top flight and Rayo, carrying a greater threat in front of goal, came out on top.