Barcelona threw away a 2-0 lead and saw their La Liga hopes receive a major setback as they drew at Levante.
Lionel Messi put the visitors ahead with a well-controlled low volley before they doubled their lead when Pedri converted from Ousmane Dembele’s cross following Messi’s through ball.
But Gonzalo Melero headed one back and Jose Luis Morales volleyed in for 2-2.
Barcelona retook the lead with Dembele’s powerful shot, but Sergio Leon got a late equaliser for Levante.
Barca move up to second, above Real Madrid, but would have gone top with a victory and are one point behind leaders Atletico Madrid, who have a game in hand.
Atletico have three matches left and will become Spanish champions for the first time since 2013-14 if they win all of them.
Barca midfielder Sergio Busquets admitted his side’s chances of winning La Liga for the 27th time, were now slim.
“There are very few options for us to win the league now,” he said.
“It feels terrible. We weren’t able to win the game, we started well, got the advantage and the second goal, but could not get a third. As has happened too many times, errors have cost us.
“The point means very little to us. We weren’t precise with our passing and they took full advantage. We had our chances but we paid for our mistakes – we’ve not had a good second half.
“It is our fault and we take responsibility – we allow teams to score too easily against us.”
Barcelona looked completely in control after scoring twice in the opening 34 minutes, against a Levante side who needed one point to be certain of avoiding relegation.
However, with full-back Sergi Roberto coming on and going into an unfamiliar central defensive position, Ronald Koeman’s side began to look fragile and conceded twice in a three-minute period.
Melero got up above the Barcelona defence to head a goal back and then Messi carelessly lost possession 30 yards from his own goal with Morales volleying in Levante’s first equaliser.
Dembele’s goal, awarded after a video assistant referee check decided Antoine Griezmann had not fouled Levante’s Jorge Miramon, restored the visitors’ lead, but Leon got ahead of Gerard Pique to flick in a late, dramatic third goal.
“In the second half we lacked intensity and I don’t know what I did wrong at the half-time period as we were superior in the first half,” said Koeman.
“They surprised us by scoring three goals and I have no explanation – I don’t know why it happened.
“In terms of intensity, we dropped and got over-relaxed. The whole team defensively was not at the level required. Conceding three goals in 45 minutes is too many for this team.”
Barcelona won the Copa del Rey last month but went out of the Champions League at the last-16 phase and could miss out on the Spanish title for a second successive season.
Atletico will go four points clear if they win their game in hand on Wednesday at home against fifth-placed Real Sociedad, before Real Madrid play at Granada on Thursday.