Defending champions Barcelona took a giant stride towards another Spanish title in their centenary year with a compelling win over Real Madrid in front of 105,000 fans.
Spanish international Luis Enrique notched two headers in the first half for the Catalan giants, after four and 36 minutes. The first was set up by Patrick Kluivert and the second by Pep Guardiola.
Real's Brazilian defender Roberto Carlos was sent off after 20 minutes for a wild tackle on Luis Figo in a St Valentine's Day clash where there was little evidence of any love between the bitter rivals.
That weakened an already fragile Real defence, which has conceded 35 goals this term.
There was no way back for Real after Enrique's second goal, and another Brazilian, Rivaldo, emphasised the Nou Camp outfit's superiority with a third 12 minutes from time, dribbling through the defence and scoring with a low shot.
It completed a miserable sequence for the world club champions at the Nou Camp: they have not won at the Catalan citadel since 1983.
Celta Vigo's title challenge received a further setback with a 2-1 defeat at the hands of Valladolid. Jose Luis Caminero grabbed a 27th-minute lead for the home team, but Israeli international Haim Revivo levelled the match for Celta on the hour. Lopez Moreno Alberto, however, struck the winner after 78 minutes.
The most expensive player in the world, Brazilian Denilson, hit a rare goal for Real Betis, saving a point for the Seville side with his 65th-minute strike. Pedro Alvarez Munitis had put Santander in front after 18 minutes.
It was a rare moment of respite for Denilson, who has found it hard to live up to his £21 million price tag and has also had his differences with coach Javier Clemente.
Real Zaragoza had to share the points with Alaves despite taking a fourth-minute lead through Jose Ignacio. Lopez Segu Gerard equalised five minutes before the break. Athletic Bilbao, meanwhile, drew 0-0 with Extremadura.
Mallorca are the closest challengers to Barca after Saturday's 1-0 home win over Real Sociedad.
Argentinian Leonardo Biagini scored the vital goal from a penalty after 62 minutes and Mallorca's defence, on which their success has largely been built, held out.
Atletico Madrid's poor run continued with an embarrassing 2-1 home defeat by Espanyol at the Vincente Calderon Stadium.
Jose Mari's solitary strike after 21 minutes gave Atletico a dream start, but goals from Arteaga (38) and Dario Silva (84) won it for the Catalan visitors.
It was the third consecutive league reverse for the team managed by former Italian national team boss Arrigo Sacchi.
A goal from Turu Flores after 51 minutes gave in-form Deportivo La Coruna the points in Saturday's other match at home to Salamanca.
