Real Madrid have dropped to third position in La Liga after losing Saturday's El Clasico 4-0 at home to Barcelona, which has left Los Blancos six points off the summit.
Rafael Benitez's side entered the showpiece event trailing Barcelona by three points in the table, and that has now been extended after Luis Suarez (2), Neymar and Andres Iniesta struck during what was an incredible night in the Spanish capital.
Real Madrid remained second after the match, but it got worse for Benitez's team on Sunday, with Atletico Madrid's 1-0 win at Real Betis seeing the 2013-14 league champions move above their rivals in the table.
Week 12's action opened from the Anoeta on Saturday afternoon and it was a special occasion for Eusebio Sacristan, who led Real Sociedad to a 2-0 win over Sevilla in his first game since replacing David Moyes at the Basque club.
Following the Clasico, Espanyol recorded a 2-0 win over Malaga, which has ultimately left Javi Gracia's side bottom of the table, while Las Palmas came from behind to claim a 1-1 draw at Valencia, who remain in seventh position.
Celta Vigo also dropped out of the top four on Saturday after losing 2-0 at Deportivo La Coruna, who continue to impress in the new campaign.
On Sunday, Levante moved off the bottom of the table with a vital 3-0 win at fellow strugglers Sporting Gijon, before the points were shared between Villarreal and Eibar, who sit fourth and sixth respectively in the division.
There was also a big win for Granada, who put two unanswered goals past Athletic Bilbao to move out of the relegation zone, before Atletico rounded off Sunday's action with a 1-0 win at Betis.
The round of fixtures drew to a close on Monday, however, as Getafe and Rayo Vallecano shared the points in a 1-1 draw in the Spanish capital.
Here, Sports Mole picks out its star XI from week 12 in Spain's top flight.
Claudio Bravo (Barcelona)
Such was Barcelona's attacking performance against Real Madrid, not much was spoken about their work down the other end. Defensively they were strong, but they would not have kept a clean sheet without the performance of Bravo, who made a host of excellent saves, especially in the second period. The stopper's best moment came in the latter stages when he kept out a thumping Cristiano Ronaldo header.
Diego Godin (Atletico Madrid)
If Atletico are to challenge for the league title this season, they will need Godin in top form. The centre-back was immense for his team during their 2013-14 title-winning campaign and his performance against Betis was one of his best in recent memory. The Uruguay international twice suffered big blows to his head, but even with a bandaged cut, he was prepared to go in where it hurts all night. He was a monster in Seville.
Zouhair Feddal (Levante)
It has been a very difficult season for Levante thus far, but they moved off the bottom of the table at the weekend with an impressive 3-0 win at Sporting Gijon. Deyverson, who also makes this XI, scored twice for the visitors, but the other came from Feddal, who also set up his striker's second of the match. It was an excellent all-round performance from the defender, who contributed at both ends of the field.
Sidnei (Deportivo La Coruna)
Deportivo have actually only been beaten twice in the league this season and they continued their strong start to the campaign with a 2-0 win over Celta Vigo on Saturday. Sidnei's performances have coincided with Depor's improvement and the Brazilian was once more in impressive form at the weekend. Celta have scored bundles of goals this season, but just could not find a way past Sidnei in La Coruna.
Jonathan Viera (Las Palmas)
Las Palmas remain inside the relegation zone in La Liga after 12 matches, but the Canary islanders picked up an impressive point away to Valencia at the weekend. It was a big game for Viera on his return to the Mestalla and the Spaniard impressed for the visitors. Las Palmas trailed to an eight-minute strike from Paco Alcacer, but Viera's effort just before the hour ensured that his team took a point from the match.
Andres Iniesta (Barcelona)
Not many Barcelona players are clapped off the field at the Bernabeu, but Iniesta was one of them at the weekend. The midfielder might now be the wrong side of 30, but he remains one of the classiest players in world football. It was the Spaniard that set up his side's second in El Clasico, before scoring the third himself early in the second period. In the 77th minute, the Catalan left the field to a standing ovation.
Xabi Prieto (Real Sociedad)
It has not exactly been the start to the season that Sociedad would have wanted, and club captain Prieto struggled for football under former boss David Moyes. The Spaniard was back in the team and back among the goals at the weekend, however, as Sociedad recorded a vital 2-0 win over Sevilla. Both of the home side's goals came in the final 20 minutes and it was Prieto that rounded off the scoring 13 minutes from time.
Hernan Perez (Espanyol)
Espanyol's form has been a little shaky in recent weeks and they really needed a good performance and indeed result against Malaga on Saturday evening. It was not the prettiest of games in Barcelona, but Perez was in wonderful form for the hosts, scoring both goals in their 2-0 win. Everything good about Espanyol's performance came from the 26-year-old, whose cleverness in a forward position proved key in the home win.
Deyverson (Levante)
The 24-year-old has found it difficult to adapt to life in Spain following a summer move from Belenenses, but the Brazilian showed signs of his talent in Levante's 3-0 win at Sporting Gijon on Sunday. The striker scored twice in the first period of the contest and could have had a couple more during what was a strong second-half performance. The hosts simply struggled to deal with Deyverson's movement during the clash.
Luis Suarez (Barcelona)
It is difficult to put into words just how impressive Suarez and Neymar have been for Barcelona in recent weeks and both played key roles in Saturday's Clasico. Suarez both opened and completed the scoring against Real Madrid, with his movement and tenacity proving too much for Los Blancos to handle. Any questions surrounding his move to Camp Nou last summer have long been answered.
Neymar (Barcelona)
The second part of Barcelona's sensational double-act, Neymar continued his excellent run of form against Real Madrid. The Brazilian scored his 14th goal of the season five minutes before the interval, showing composure to slide the ball under Keylor Navas. The tricks are still there, but now there is an end product from the Brazil skipper. On current form, he is surely the best player in the world.
