Lionel Messi scored a dramatic late winner as Barcelona beat Atletico Madrid 1-0 at the Wanda Metropolitano Stadium to return to the summit of LaLiga on Monday (AEST).
Real Madrid had temporarily claimed top spot on Saturday after a 2-1 win at Deportivo Alaves but Barca's victory put them ahead on goal difference.
Atletico had enjoyed the best of the chances in an engrossing contest but remain winless in 19 LaLiga games against the Catalans.
Ernesto Valverdes's side were indebted to goalkeeper Marc-Andre ter Stegen for two breath-taking saves in the first half.
Diego Simeone's Atletico went close to opening the scoring in a lively first half when Mario Hermoso struck a low angled shot against the post.
Atletico were then twice denied by the inspirational Ter Stegen. The German first blocked an instinctive Hermoso effort from close range, then managed to somehow keep Alvaro Morata's powerful header out.
Barca rarely threatened before the half-time, although Gerard Pique's had nodded against the crossbar.
The visitors improved slightly after the break, although Luis Suarez and Messi struggled to find a way past a disciplined and organised Atletico defence.
Pique was fortunate not to be shown a second yellow card for a callous sliding foul on Morata with 20 minutes left and the game appeared set to end in a goalless draw.
However, with four minutes left on the clock Messi delivered after a lightning quick move on the edge of the Atletico penalty area.
The Argentina forward received the ball from Suarez and emphatically curled a low shot past Jan Oblak to seal the win.
What does it mean? Barcelona show character of champions
Real Madrid's victory the previous day increased the scrutiny on Barca, but they secured the kind of victory associated with proven champions.
On a day when they were largely second-best Barcelona came away from Madrid with a vital victory and almost inevitably Messi was the man to provide the moment of quality.
Simeone, meanwhile, is still searching for his first LaLiga win over Barcelona since he took charge of Atletico in 2011.
Tremendous Ter Stegen showcases class
Barcelona goalkeeper Ter Stegen can spend some matches twiddling his thumbs. However, this was not one of them and he was an inspirational presence between the sticks for the Catalan side.
Joao Felix flatters then fades
Portuguese international Joao Felix showed some nice touches in the first half for Atletico but the 20-year-old attacking midfielder's influence on the game fizzled out. Atletico fans questioned his substitution, but it was the correct decision.
Atletico travel to Villarreal on Friday in LaLiga, while Barcelona are in domestic action 24 hours later when they host Real Mallorca.