Sergio Aguero was forced off with what appeared to be a chest injury as Barcelona drew their first match since the sacking of Ronald Koeman.
Aguero went down clutching the top of his chest and received treatment for several minutes before being helped off the pitch just before half-time.
Memphis Depay opened the scoring in the second half with a curling effort.
Luis Rioja earned Alaves a point after rounding goalkeeper Marc-Andre ter Stegen.
The point keeps Barcelona in ninth place – eight points behind La Liga leaders Real Madrid, who beat Elche 2-1 earlier on Saturday.
In front of just over 37,000 supporters at the Nou Camp, interim coach Sergi Barjuan’s side went closest to a first-half opener when Eric Garcia’s downward header was saved by Alaves goalkeeper Antonio Sivera.
Depay was inches away from restoring Barcelona’s lead soon after Alaves’ equaliser, but the Dutchman could only steer his effort from Gavi’s pass against the post.
Philippe Coutinho, who replaced Aguero late in the first half, stung Sivera’s palms with a dipping shot as the visitors held on for their first point at the Nou Camp since 2016.
- 1ter Stegen
- 22MinguezaSubstituted forEzzalzouliat 80′minutes
- 3PiquéSubstituted forLengletat 70′minutes
- 28González IglesiasSubstituted forBalde Martínezat 80′minutes
- 30Paez GaviriaSubstituted forPuig Martíat 70′minutes
- 19AgüeroSubstituted forCoutinhoat 41′minutes
- 6Puig Martí
- 13Murara Neto
- 17de Jong
- 26Peña Sotorres
- 31Balde Martínez
- 13SiveraBooked at 45mins
- 23Navarro JiménezSubstituted forAguirregabiriaat 20′minutes
- 3DuarteBooked at 82mins
- 20PonsSubstituted forPinaat 62′minutes
- 15MoyaSubstituted forGarcía Alonsoat 80′minutes
- 17MéndezSubstituted forPellistriat 62′minutes
- 9JoseluSubstituted forSyllaat 80′minutes
- 14García Alonso
- 31Ferrer Owono
- Jorge Figueroa Vázquez
Match ends, Barcelona 1, Alaves 1.
Second Half ends, Barcelona 1, Alaves 1.
Dangerous play by Eric García (Barcelona).
Martín Aguirregabiria (Alaves) wins a free kick in the defensive half.
Corner, Barcelona. Conceded by Víctor Laguardia.
Hand ball by Riqui Puig (Barcelona).
Attempt saved. Florian Lejeune (Alaves) header from the centre of the box is saved in the centre of the goal. Assisted by Manu García with a cross.
Foul by Balde (Barcelona).
Martín Aguirregabiria (Alaves) wins a free kick on the right wing.
Philippe Coutinho (Barcelona) wins a free kick in the attacking half.
Foul by Florian Lejeune (Alaves).
Attempt missed. Philippe Coutinho (Barcelona) right footed shot from outside the box is high and wide to the right. Assisted by Eric García.
Attempt missed. Philippe Coutinho (Barcelona) right footed shot from outside the box is just a bit too high from a direct free kick.
Rubén Duarte (Alaves) is shown the yellow card for a bad foul.
Abdessamad Ezzalzouli (Barcelona) wins a free kick in the attacking half.
Foul by Rubén Duarte (Alaves).
Substitution, Barcelona. Abdessamad Ezzalzouli replaces Óscar Mingueza.
Substitution, Barcelona. Balde replaces Nicolás González Iglesias.
Substitution, Alaves. Manu García replaces Toni Moya.
Substitution, Alaves. Mamadou Sylla replaces Joselu.