Gerard Pique scored a late equaliser as Barcelona drew at Espanyol to set a club record of 22 games unbeaten at the start of the La Liga season.
Philippe Coutinho hit the bar in the first half before Gerard Moreno’s header gave city rivals Espanyol the lead midway through the second.
With only eight minutes left, defender Pique headed home substitute Lionel Messi’s free-kick.
Atletico Madrid beat Valencia 1-0 to cut Barca’s lead to nine points.
Angel Correa scored the winning goal for Atletico in the second half, while fourth-placed Real Madrid, who drew 2-2 with Levante on Saturday, trail Barcelona by 19 points.
Pique, who was booed throughout by the Espanyol fans, angered them further by raising his finger to his lips to celebrate his equaliser.
Barcelona beat Espanyol to reach the Spanish Cup semi-finals last week, after which Pique described their rivals as “Espanyol de Cornella” in reference to the suburb where they play.
There was little drama early in heavy rain at the RCDE Stadium, where Espanyol have not beaten Barca in a league game, until Coutinho curled a shot from the edge of the box against the underside of the bar.
The hosts responded with Leo Baptistao dispossessing Andres Iniesta before firing straight at Marc-Andre ter Stegen, and the Brazilian striker also headed over from a Marc Navarro cross.
Barcelona’s Luis Suarez curled a free-kick narrowly over, although Espanyol thought they had scored in the first minute of the second half when the ball had gone out before Baptistao cut back for Esteban Granero to convert.
Messi came on in the 59th minute but seven minutes later Baptistao won the ball in midfield and Sergio Garcia whipped a superb right-wing cross into the box, where Moreno got behind Pique to head home his 12th goal of the season.
But from Messi’s free-kick deep on the left wing, Pique scored to take Barca past the 21-game unbeaten run set by Pep Guardiola’s side in 2009-10.