Hugo Guillamon fired the hosts level after Joao Felix had put Barca ahead early in the second half.
Barcelona lost further ground at the top of LaLiga as Valencia fought back to draw 1-1 at the Mestalla.
Joao Felix had put Barca ahead early in the second half, but Hugo Guillamon fired the hosts level with 20 minutes left.
The draw left Barca in third, but having played a match more than both Real Madrid and leaders Girona as the pressure continues to increase on manager Xavi.
Valencia, who had lost three of their last four league matches, created an early chance when Roman Yaremchuk spun to fire goalwards, but Barca keeper Inaki Pena made a smart save down to his left.
At the other end, Robert Lewandowski – without a goal in his last three away LaLiga games – had a shot deflected wide, although the ball had gone out of play in the build-up.
Pena was again called into action in the 16th minute as he got down to clear Cristhian Mosquera’s close-range header.
Valencia keeper Giorgi Mamardashvili saved Lewandowski’s drive from the edge of the penalty area in a lively spell.
The Mestalla crowd were soon calling for a penalty when Pepelu went down under a clumsy challenge from behind by Raphinha, but the referee was not interested.
Mamardashvili had to be alert to parry away an acrobatic effort from Lewandowski before Pedri flashed a rising drive over from the edge of the Valencia box.
Valencia winger Fran Perez hit a low ball through the Barcelona six-yard box which just needed a touch to turn it into the net.
Barcelona, beaten 4-2 at home by Girona last weekend, looked to step up the tempo at the start of the second half, with Ilkay Gundogan sending a first-time shot wide before the deadlock was broken in the 55th minute.
Frenkie De Jong chipped a ball down the right for Raphinha, who cut a pass back through the six-yard box for Felix to tap in at the far post.
Tempers threatened to boil over just after the hour mark when Perez flew into a challenge on Gundogan, and was swiftly shown a yellow card.
Mamardashvili produced a fine low reaction save at his near post after Raphinha had pulled the ball back from the goalline to rifle in an angled drive.
Valencia were back on level terms with 20 minutes left.
Guillamon fired a shot into the top-right corner after Barcelona had failed to clear a high ball into the penalty area from Perez, who was ruled onside following a VAR review.
Mamardashvili made another reflex stop when Barca substitute Ferran Torres latched onto an angled ball in from De Jong.
Barcelona pushed for a winner, but Raphinha was denied at the far post by a brilliant block from Yarek Gasiorowski on the line after Mamardashvili had saved the Brazilian’s initial effort.