Barcelona's lead over Real Madrid atop the LaLiga standings evaporated on Saturday after they were held to a 1-1 home draw by local rivals Espanyol in a bad-tempered clash in which both sides were reduced to 10 men.
Madrid had taken the top spot on Friday with a 2-0 win at Real Valladolid, putting pressure on Barcelona to respond against an Espanyol side battling to avoid relegation.
Defender Marcos Alonso put Barcelona in front at Camp Nou, before Joselu converted a second-half penalty to level the game.
Barcelona started strongly, with Gavi stinging the palms of Espanyol goalkeeper Alvaro Fernandez in the sixth minute, shortly before Alonso glanced a header into the net, following a corner.
After going ahead, Xavi Hernandez's side dominated possession with their slick passing for the rest of the first half but struggled to convert any of the numerous goal-scoring chances that fell their way.
They kept up the pressure after the break, but all their good work came undone as Alonso turned from hero to zero, giving away a penalty following a clumsy foul on Joselu.
Joselu picked himself up to convert the spot-kick, calmly rolling it straight down the middle to make it 1-1 in the 73rd minute.
Tempers flared in the aftermath of the equaliser, with Barcelona's Jordi Alba being sent off after receiving back-to-back yellow cards for vociferous protests against the referee.
Espanyol's Vinicius Souza was then shown a second yellow card for a foul on Robert Lewandowski two minutes later.
Defender Leandro Cabrera was also shown a red card for kneeing Lewandowski in the back after he was brought down by Souza, but a VAR review let Espanyol off the hook.
Spanish referee Antonio Mateu Lahoz, who attracted criticism earlier this month after showing 16 yellow cards in Argentina's quarter-final win over the Netherlands at the World Cup, went to the monitor before overturning his decision.
Espanyol goalkeeper Fernandez kept his side in it with a couple of fine stops towards the end of the match, keeping out a header from Andreas Christensen and a low shot from Lewandowski, as Barcelona were unable to find a winner.
Barcelona remain on top of the standings due to their superior goal difference, despite being level with rivals Madrid on 38 points from 15 matches, while Espanyol move up to 16th.