Sevilla missed the chance to move six points clear at the top as they slipped to a 2-1 defeat at Real Zaragoza, as La Liga returned after the winter break.
Real Zaragoza started brightly and opened the deadlock after 14 minutes as Carlos Diogo glanced a header from Andres D'Alessandro's corner in off the post.
They doubled their advantage six minutes into the second half when Andres Palop could not hold Diego Milito's (pictured) close-range effort and the Argentine forward tucked home the rebound.
Sevilla pulled a goal back after 71 minutes as Luis Fabiano poked home Daniel Alves' excellent low cross.
Fabiano looked set to grab an equaliser moments later but was brilliantly denied by Cesar, and Zaragoza resisted a late onslaught to cling on for victory.
As the final whistle sounded there was even more drama, with Fabiano and Diogo becoming embroiled in a fistfight.
Elsewhere, struggling Real Sociedad made the perfect start to 2007 with a 2-1 win over Osasuna, with Mikel Aranburu securing the points one minute from time after Raul Garcia (56) had cancelled out Xabier Prieto's penalty.
High-flying Atletico Madrid were held to a goalless draw by bottom club Gimnastic de Tarragona.
Click below for individual match summaries: