Barcelona need just two points from their four remaining Spanish Primera Liga fixtures to defend their title.
The Champions League finalists beat Cadiz 1-0 thanks to an early goal from FIFA World Player of the Year Ronaldinho.
Elsewhere, Celta Vigo boosted their campaign for a Champions League spot by beating Deportivo La Coruna 2-0 in the Galician derby.
David Silva and Jesus Perera scored the goals for Celta against Deportivo who had Fabricio Coloccini sent off.
Real Betis and Athletic Bilbao edged towards safety with a 1-1 draw. Jesus Lacruz equalised for Bilbao after Robert had opened the scoring for the Seville side.