Barcelona, which is aiming to regain the title after Madrid claimed a record 30th Primera Liga crown last year, dominated against Osasuna at the Camp Nou. Xavi volleyed into the net to finally end the visitors' resistance. Madrid had suffered its third defeat of the campaign on Saturday, losing 2-0 at Almeria. It remains in top spot with 53 points. Barcelona has 47 points.
Elsewhere, Villarreal drew 1-1 against Real Mallorca, Valencia won 2-0 at Real Valladolid, Atletico Madrid tied 1-1 against Murcia, and Sevilla beat Recreativo Huelva 2-1.
Inter, the two-time defending Italian champion, extended its lead to eight points in Serie A after Zlatan Ibrahimovic's 34th-minute penalty kick against Empoli secured a ninth win in 10 games.
Second-place Roma suffered a 3-0 loss at Siena, while Juventus was held to a 1-1 home draw by Cagliari.
Inter has 53 points, Roma is on 45 points, with Juventus four points further back.