Lionel Messi's brace could not save Barcelona as they lost to Real Betis in a seven-goal thriller on Sunday.
Betis held on for their first win at Camp Nou since 2005, taking maximum fruits for their bravery, while Marc-Andre ter Stegen gifted the visitors a goal and Ivan Rakitic was sent off.
The No 10 returned after less than a month out with an arm injury, lining up in attack alongside Luis Suarez and Malcom, who was rewarded for his goal against Inter midweek.
However, Ousmane Dembele was cut from the squad completely after he missed training on Thursday, amidst reports the winger went AWOL for an hour and a half.
Elsewhere, Samuel Umtiti recovers from a knee injury to take his place on the substitutes' bench as Clement Lenglet partners Gerard Pique once more.
Betis, for their part, had won just two of their last seven games and drawn their previous two but had as many ex-Blaugrana players starting in Marc Bartra and Cristian Tello.
Junior led Betis’ charge down the left in the first half, and he gave his side the lead when he cut inside and kept his cool, before placing a finish past Ter Stegen.
The Andalusians then doubled their advantage before the break, 37-year-old Joaquin Sanchez pouncing on a second cross into Barca’s box.
Ernesto Valverde threw on Arturo Vidal for the second half, but it was Messi who initiated a possible comeback, converting a penalty after Tello had pulled down Jordi Alba in the box.
Nonetheless, Ter Stegen spilled Giovani Lo Celso’s powerful effort from close range and Sergio Canales came off the bench to slide home a low cross.
Vidal did pull a goal back and VAR validated Messi scrambling in the midfielder’s cutback at the death, but the comeback wasn’t to be, leaving the top of La Liga up for grabs.
Barcelona 3-4 Real Betis
Messi pen 68, 90, Vidal 79, Rakitic sent off 81 (B) Junior 20, Joaquin 34, Lo Celso 71, Canales 83 (RB)
Barcelona: Ter Stegen; Sergi Roberto, Pique, Lenglet, Alba; Rakitic, Busquets (Alena 69), Arthur (Arturo Vidal 46); Messi, Suarez, Malcom (Munir 57)
Real Betis: Pau; Mandi, Bartra, Sidnei; Tello, William, Guardado, Lo Celso (Inui 87), Junior; Joaquin (Canales 62), Loren (Sergio Leon 76)
Referee: Mateu Lahoz