The Blaugrana saw key calls go against them either side of half-time in Las Palmas and are only five clear ahead of Sunday's visit of the Rojiblancos
There is still some margin for error for Barcelona in the title race – but not very much.
Ernesto Valverde's side were held to a 1-1 draw by lowly Las Palmas on Thursday night and even though they remain unbeaten in La Liga, their lead at the top of the table has now been cut to five points.
After Lionel Messi fired Barca into the lead after 21 minutes with a fantastic free-kick, it looked as if the Blaugrana would coast to another comfortable win.