Real Madrid passed up a chance to close the gap on La Liga leaders Barcelona as they slumped to a 1-0 loss away to Villarreal on Sunday.
Barca were held to a 2-2 draw by Deportivo La Coruna on Saturday and Atletico Madrid came from behind to beat Athletic Bilbao earlier on Sunday to draw level on points with the defending champions.
Madrid were unable to emulate their cross-city rivals as they failed to find a response to an eighth-minute opener from Roberto Soldado – the striker who began his career at the Santiago Bernabeu.
Villarreal, who now lie fifth in La Liga, three points behind Madrid, were unfortunate not to enjoy a more handsome lead after a swashbuckling first-half performance at El Madrigal.
They were not so convincing in their gritty attempts to hold on after the break but some wayward finishing from Madrid forward duo Cristiano Ronaldo and Karim Benzema came to their aid.
A third Liga loss of the season leaves Rafael Benitez's men five points off the pace.
Seemingly encouraged by the frailties shown by Madrid's title rivals this weekend, Villarreal tore into their more illustrious opponents from the first whistle.
Cedric Bakambu was central to much of the hosts' vibrant play and a storming run scattered the Madrid defence in the fourth minute - the Congolese forward finding Jonathan dos Santos, who thudded a strike against the inside of the post.
The breakthrough was not far away though, as Bruno caught Luka Modric in possession and Bakambu fed Roberto Soldado to send a crisp finish through Keylor Navas' legs.
Pepe then made a last-ditch challenge with Soldado threatening to inflict further damage on the end of a Bakambu cross.
The latter player should have scored the goal his efforts merited in the 27th minute but watched a scuffed finish dribble wide, having beaten Pepe in a foot race.
Bakambu also swivelled to shoot over on the end of another sweeping Villarreal attack and Madrid's array of attacking talents were largely passengers as Benitez's men escaped the first half with a slender deficit.
Benzema led the charge for Real when the action resumed – sending a snap shot narrowly wide before blazing over from a Gareth Bale cross.
Villarreal did not shirk the challenge and responded with Soldado forcing Navas into a fine save from 20 yards after 50 minutes.
But the hosts' defensive vulnerabilities were now a more visible feature than their quicksilver attacks and Navas' opposite number Alphonse Areola got down to touch around the post when Bale got the better of Victor Ruiz and sent a bobbling shot towards the bottom corner.
Ronaldo punctuated a quiet outing by striking the outside of the near post from a tight angle and the Portugal star could not capitalise when Benzema and Villarreal defender Eric Bailly tumbled in front of him, hacking a 68th-minute volley over.
It was soon Benzema's turn to endure more frustration in front of goal when he misjudged a back-post header from Bale's pinpoint centre.
James Rodriguez fired a rasping drive narrowly wide but, after back-to-back Liga wins following the 4-0 Clasico humiliation last month, Benitez was left to reflect on another damaging setback.
