Lionel Messi has scored 15 goals and produced 10 assists in his first 17 league games of the season. Photo: Reuters
Barcelona restored their three-point lead at the top of La Liga with a comfortable home win over Celta Vigo.
Ousmane Dembele opened the scoring on 10 minutes, following up Lionel Messi's saved shot after the Argentine had initially played a delightful ball through to Jordi Alba.
Messi doubled the lead just before half-time, finishing neatly from the edge of the area as the defence parted.
Atletico Madrid had moved level on points with Barca by beating Espanyol.
Antoine Griezmann's penalty gave Atletico a 1-0 victory, but the Catalans re-established their advantage with a fourth straight league win without conceding.
After a slow start, Celta Vigo grew into the contest but ultimately struggled to create clear-cut opportunities - captain Hugo Mallo wasting their best chance in the first half as he failed to hit the target from close range.
Home goalkeeper Marc-Andre Ter Stegen was forced into a goalline save from a dangerous corner, before denying substitute Pione Sisto in the closing stages.
At the other end, Ruben Blanco did well to deny Dembele, then produced a good save to keep out Nelson Semedo's effort as Barcelona cruised to victory in their final match of 2018.
Defeat leaves Miguel Cardoso's Celta Vigo 10th in La Liga.