The Spanish giants remain top of the table, with four points before the game, and were brimming with confidence after their Champions League win over Newcastle.
With Real Madrid breathing down their neck, they need to continue their impressive league form of four wins to maintain the point gap.
However, they had to work hard for the win and secured a narrow 1-0 victory over Vallecano to go seven points clear
As it happened
Hansi Flick made three changes to the Barcelona starting XI that beat Sevilla 5-2 last week. Rayo Vallecano manager Inigo Perez, meanwhile, has made six changes to the side that held Levante 1-1.
The home side started the game poorly but were able to take the lead from a corner kick. Captain Ronald Araujo won a physical battle with Pathe Ciss and headed in an inswinging corner to give Barcelona the lead.
Barcelona tried to get more goals before the half-time break, but they were unable to create goal-scoring chances.
There was not much difference in the second half, as both teams struggled to get going in the game.
The host continued to struggle with their performance and could only hold on to their one-goal lead, stopping the visitors from getting an equaliser.
The narrow win put them seven clear of Madrid, who are yet to play and are edging closer to winning the title.