A stoppage-time goal from Angel Lafita snatched a dramatic 2-2 draw for Getafe at Barcelona, which could prove fatal to the Catalan club's hopes of retaining the Primera Division title.
Gerardo Martino's men began the day four points behind leaders Atletico Madrid but a victory looked likely when Alexis Sanchez fired home in the second half after Lafita had earlier cancelled out Lionel Messi's opener.
But struggling Getafe grabbed an unlikely point with another equaliser from Lafita - 90 seconds into stoppage time - and Barca will find themselves six points behind Atletico if the Madrid club beat Levante on Sunday, with the two sides set to meet on the final day of the season.
Barca could also find themselves down to third spot by the end of the weekend with Real Madrid due to face Valencia on Sunday night.
Getafe, meanwhile, are now unbeaten in three La Liga matches to keep their noses above the relegation zone.
Barca were chasing their third successive league win but apart from an early strike from Adriano, which was held by Getafe goalkeeper Julio Cesar, there was little to write home about in the opening 20 minutes.
However, Messi finally brought the Nou Camp faithful to their feet after 22 minutes. Dani Alves played a perfectly weighted ball into the area for the Argentina striker, who planted a left-footed shot into the top left corner to break the deadlock.
Sanchez then threatened to add a second within minutes but Cesar was able to get down to block the shot.
Getafe had not got into the match at all so far but things looked to be changing when a free-kick from Pablo Sarabia only just cleared the crossbar.
And the scores were level after 36 minutes thanks to Lafita, who was the beneficiary of another Sarabia set-piece to stab home a low strike.
Barca took time to recover from the blow although Alexis had the final chance of the half, driving over from 12 yards out.
And that seemed to fire the home side up for the restart, with Cesar saving shots from Andres Iniesta and Messi just moments into the second half before Alexis smacked the crossbar with a 54th-minute header as Barca ramped up the pressure.
The Chilean forward then got the goal he merited after 67 minutes, steering the ball into the bottom right corner with his left foot.
The shots continued to rain in from the home side, with Pedro, Cesc Fabregas and Dani Alves all threatening as a home win looked on the cards - until Lafita popped up in the second minute of stoppage time to head in Jaime Gavilan's cross and leave Barca's title defence hanging by a thread.