Barcelona dropped points in La Liga on Saturday after Espanyol held them to a 2-2 draw in a Catalan derby at the RCDE Stadium.
The visitors started the game poorly and fell behind midway through the first half when an unmarked David Lopez nodded Marc Roca's free-kick past goalkeeper Neto.
Barcelona struggled to cause Espanyol problems but did go close to an equaliser just before half-time when Luis Suarez saw a shot hit the post.
The Uruguay international levelled the scores early in the second half from a Jordi Alba cross and then teed up Arturo Vidal to head Barcelona in front on the hour mark.
Barcelona were reduced to 10 men when Frenkie de Jong was sent off on 75 minutes, and Espanyol made the most of their man advantage by levelling late on through Wu Lei.
The champions saw plenty of the ball in the opening stages but were slow and predictable in possession and did not threaten Diego Lopez in the Espanyol goal.
The first serious attack of the game brought the opening goal for the visitors. De Jong conceded a foul on the edge of the area from which Roca delivered an accurate ball for Lopez to nod past Neto (UK video only):
Barcelona offered little in the way of a response initially. Lionel Messi managed a tame shot, which was comfortably saved by Lopez, and then went tumbling in the box but saw his penalty appeals correctly waved away.
ESPN FC's Dermot Corrigan noted the difference in Espanyol's play under new manager Abelardo:
The champions came closer to an equaliser just before half-time. Messi forced Lopez into a save with a strong header from a Sergi Roberto cross, while Suarez toe-poked a shot on the woodwork.
Barcelona manager Ernesto Valverde made a change at half-time, bringing on Vidal for Ivan Rakitic, and the substitution helped shift the game in the visitors' favour.
Suarez needed just four minutes of the second half to fire Barca level. The striker latched on to Alba's cross to beat Lopez at his near post with a clinical finish.
The Uruguay international then teed up Vidal to place a firm header past Lopez at the far post to put Barca in front nine minutes later:
10 - Luis Suárez has been involved in each one of the @FCBarcelona’s last nine goals in #LaLiga (four goals & six assists). The Uruguayan is the player to have scored & assisted both in a single LaLiga game more often (four as Karim Benzema). Key #EspanyolBarça #Derby https://t.co/pL0rDO9day
Espanyol were then offered hope of a comeback when de Jong picked up the first dismissal of his Barcelona career:
The Dutchman had already been booked for a foul on Matias Vargas and received his second yellow for pulling back Jonathan Calleri, leaving Barca to play the last 15 minutes with 10 men.
Lei came close to an equaliser for Espanyol, getting a firm header on a ball in from deep but seeing a diving Neto claim comfortably.
However, the substitute was not to be denied a second time. Vargas' pass released the winger down the right channel, and he made no mistake with a fine shot across Neto and into the far corner:
The result means Barcelona go back to the top of La Liga ahead of Real Madrid on goal difference, but they have seen their two-point advantage over Los Blancos wiped out on the opening weekend of 2020.
Barcelona play Atletico Madrid in the semi-finals of the Spanish Super Cup on Thursday at the King Abdullah Sports City in Jeddah, Saudi Arabia. Espanyol's next fixture is against San Sebastian de los Reyes in the second round of the Copa del Rey on Sunday, January 12.