Two second-half goals from Luis Suarez and Carles Alena were enough to hand the Catalans all three points on a night Lionel Messi started on the bench.
“It’s an incredibly valuable win,” coach Ernesto Valverde said. “In the end however much as people say the league is won, it has to be achieved on the field.
“We are at the gates now, needing three points more with four games ahead. It is an immense joy to be in this position after so many months of work.”
The win means Barca will be crowned champions today if Atletico Madrid fail to beat Valencia at home.