Goals from Luis Suarez and Jordi Alba saw Barca past the hosts in a 2-0 victory, although the table-toppers were made to work hard throughout by their opponents.
That win puts the Blaugrana 10 points clear of second-placed Atletico, who will have the chance to restore the gap to seven on Sunday away to Athletic.
It also means that Barcelona are now 31 games unbeaten in the top flight, a mark they have achieved just once before in their history.
One must look back to 2011 to find the last time the club achieved such a feat, under the stewardship of Guardiola.
The current Blaugrana side, who have won 26 and drawn five of their last 31 outings (seven under Luis Enrique) are also fighting on three fronts.
And, if they keep up their winning ways, La Liga at least looks almost certain to return to Catalunya for the third time in the last four seasons.