Barcelona's inconsistent start to their title defence continued with a 4-3 reverse against Celta Vigo at Balaidos on Sunday.
The hosts raced into a surprise three-goal lead through Pione Sisto (22'), Iago Aspas (31') and a Jeremy Mathieu (33') own-goal, before Barca almost staged a comeback of note as Gerard Pique (58') and Neymar (64' pen) reduced the deficit to one.
However, Pablo Hernandez extended Celta's advantage 13 minutes from time, only for Pique to score again on 87 minutes to make for a nervy finish to the match.
Luis Enrique's side made a promising start, though, with Mathieu firing over from distance on six minutes before Luis Suarez tested Sergio Alvarez with a strike from inside the area on the left five minutes later.
The Galicians threatened for the first time soon afterwards as Hernandez failed to direct his header on target from Daniel Wass' 13th-minute corner, while back up the other end Sergi Roberto went close with a long-range shot that missed the goal by inches.
But it was the Celticos who broke the deadlock on 22 minutes when Sisto beat Marc-Andre ter Stegen with his shot from inside the area on the right and the keeper had to be alert to deny Aspas and Cabral from extending their lead soon afterwards.
But Ter Stegen had to take the ball out the back of his net again on 31 minutes after Aspas fired home from inside the box and things got worse for the Catalan giants just two minutes later when Mathieu put past his own keeper.
Barça go down 4-3 at Celta after a spirited second half comeback: (Sisto, Aspas, Mathieu (og) and P.Hernández – Piqué 2, Neymar pen.) pic.twitter.com/d0FC1P9z87
— FC Barcelona (@FCBarcelona) October 2, 2016
Barca needed a response but they had to wait until after the break to make a game of it. Pique pulled one back on 58 minutes with a header from Andres Iniesta's corner and the comeback looked on six minutes later when Neymar slotted his spot-kick into the bottom left corner of the goal, after Andre Gomes had been brought down by Nemanja Radoja for a penalty.
However, Celta gave themselves some breathing space on 77 minutes with their fourth goal, a corner which was headed home by Hernandez, although Pique popped up with another headed goal with three minutes left to set up a tense finale.
Meanwhile, Malaga came from an early goal down as they battled back to beat Athletic Bilbao 2-1 at La Rosaleda.
Los Leones took the lead through Aritz Aduriz after just three minutes, although they had to play the entire second half with 10 men following the 36th-minute dismissal of Mikel Balenziaga.
The Basque outfit held on until the final eight minutes when quick-fire goals from Sandro Ramirez (82') and Duda (83') secured the comeback win, although Bakary Kone was also sent off for the Boquerones in stoppage time.
Elsewhere, Villarreal maintained their unbeaten start to the league campaign as they shared the spoils in a 0-0 draw with struggling Espanyol at the RCDE Stadium.