The Catalans have had their troubles in recent weeks, but they clinched a fourth league title in five years.
Jose Mourinho's side went into the clash at Cornella-El Prat knowing that it had to win to prolong its rival's title celebrations but could only muster a 1-1 draw, with Gonzalo Higuain canceling out Christian Stuani's opener.
The title success is the 22nd in the Catalan giant's 113-year history and its fourth in the last five seasons after relinquishing its grip on the championship to Real Madrid last term.
Ahead of the Vicente Calderon to face Atletico Madrid on Sunday, Barca has 88 points, 12 short of equaling Madrid's record tally of 100, which it set last year.
Los Blancos, meanwhile, have 81 and just two games to spare, meaning they cannot overhaul the Liga leader.
Tito Vilanova's troops have netted 105 goals after 34 games, 20 short of the best-ever total and have lost just two games, against Real Sociedad and Real Madrid.
They are unbeaten on home soil this term in La Liga, but were eliminated from the Copa del Rey by Madrid and the Champions League by Bayern Munich.
Barca and Atleti meet on Sunday.