Levante stunned 10-man Real Madrid 1-0 on Sunday, with Arouna Kone's second-half goal giving the Spanish powerhouse its first loss of the league season.
Madrid played a man down from the 40th after Sami Khedira received his second yellow card.
Cristiano Ronaldo came off the bench at halftime to try and spark Madrid, but Kone converted Levante's numerical advantage into the 68th-minute winner.
The loss left Madrid one point behind Barcelona and two points behind league leaders Valencia and Real Betis.
Madrid coach Jose Mourinho had no doubts who was responsible for the loss.
''The fault, in my opinion, lies with one of my players who knew about this type of situation and yet still fell into the trap,'' the Portuguese coach said. ''In the (training) sessions we showed images just like those of the sending off of Khedira, and I thought that this was not going to happen and that nobody would be sent off.
''I think players have to be intelligent enough to avoid situations like this.''
But in a meeting between the teams with the smallest and largest budgets in Spain, Levante was proud to have succeeded in hanging firm with Madrid in the first half before taking advantage of its extra man later.
''We are a humble team and have to fight just to get by,'' said Levante's veteran defender Sergio Ballesteros. ''They are the team with the most economic power in La Liga and the big stars, and they can't make excuses for losing.''
Kaka was given a rare start in place of Ronaldo, who hurt his ankle during Wednesday's 1-0 win at Dinamo Zagreb in the Champions League.
Despite looking sluggish, Madrid still had chances to go ahead early.
Levante goalkeeper Gustavo Munua almost gifted Madrid a goal in the 23rd when he collided with a teammate and spilled the ball to Fabio Coentrao. The Portuguese midfielder laid off for Karim Benzema, but Ballesteros blocked his shot on the goalline.
Khedira was sent off after receiving his second yellow card for pushing over Ballesteros during a spat that broke out between the two teams over a foul disputed by Angel Di Maria.
''Clearly, when you have to play with a man less it is more difficult to circulate the ball,'' Madrid defender Sergio Ramos said. ''But the expulsion is no excuse.''
Mourinho sent on Ronaldo for Benzema at the beginning of the second half and shortly after added more firepower with Argentina striker Gonzalo Higuain substituting Coentrao.
But it was Levante that broke through when Kone sent his right-footed blast over Madrid goalkeeper Iker Casillas after Javi Venta set up the former Sevilla striker in the area.
Madrid tried to press for the late equalizer but Levante's defense had little trouble resisting until the final whistle for its first league home win in seven tries against the powerhouse.
''On grounds like this the league is also won and lost,'' Ramos said. ''We have to continue working and look ahead.''
