Barcelona twice threw away the lead to draw 3-3 at Levante on Tuesday in a potentially fatal blow to its chances of winning the La Liga title.
The draw took Barca into second place in the standings on 76 points, one behind leader Atletico Madrid and one ahead of third-placed Real Madrid, who both have a game in hand.
Lionel Messi put a dominant Barca in front after 26 minutes and then played a part in Pedri tapping in the team's second goal in the 34th after a sweeping team move.
Levante got a foothold in the game with a header from Gonzalo Melero in the 57th and talismanic forward Jose Luis Morales equalised three minutes later.
Ousmane Dembele restored Barca's lead in the 64th and looked to have sent Ronald Koeman's side provisionally top of the standings but Levante came back at it and equalised again when striker Sergio Leon netted at the near post in the 83rd.
MATCH BLOG | La Liga highlights: Barcelona, Levante play out 3-3 draw
Atletico can go four points clear of the Catalans with victory at home to Real Sociedad on Wednesday, while Real Madrid visits Granada on Thursday.
"This feels terrible, it's very difficult (to win the title) now," said Barca midfielder Sergio Busquets. "We wanted to win and put pressure on the other teams but weren't able to and errors cost us dear, as has happened too many times this season. Teams keep scoring too easily against us."
Barca had clawed its way back into the title race with a sensational run of results since January but its resurgent challenge has unravelled in its last four games, in which it has taken five points.
Koeman's side gave away the lead in a shock 2-1 loss to visiting Granada on April 29 and after beating Valencia 3-2 in its next game the club was held 0-0 at home by Atletico on Saturday, missing a chance to go above Diego Simeone's side in the table.
Busquets, who wore a protective mask against Levante after sustaining a head injury versus Atletico, admitted Barca's opportunity to win the title had practically gone.
"We have very few chances of winning the league now and it's all our fault, we made lots of errors with our positioning and we lost concentration" he added. "It wasn't just tonight, we've let a lot of points slip away from us this season, too many to fight to win the league."