But Coutinho, dressed in a black shirt dotted with white stars, was in the stands at the Camp Nou for the first.
Pione Sisto had equalised for Celta after Jose Arnaiz found the net for Barca in the first leg at Estadio de Balaidos; an away-goal that gives Barca a small advantage, although their manager, Ernesto Valverde, won't try to sit back and defend that narrow advantage.
The Catalan club on Thursday night defeated Celta Vigo 5-0 at home.
The tie petered out in the second half but French global Ousmane Dembele showed why Barca shelled out £138m for him by dribbling past three defenders from the halfway line before being denied by a desperate tackle.
"Messi is the best player in history and the best in the world by a difference", Alba told GOL after the game.
The first legs of the quarter-finals will take place on Wednesday and Thursday next week, with the return legs scheduled for a week later on January 24 and January 25.
Sevilla were comfortable 4-1 aggregate winners over Cadiz of La Liga 1|2|3 in the last round but will face a much tougher test against an Atleti side who also had things their own way in the last 16, beating third tier Lleida Esportiu 7-0.
Wissam Ben Yedder in the 31st minute and Joaquin Correa in the 54th minute were on target for manager Vincenzo Montella's team.
Numancia ended the game with 10 men after captain Dani Calvo was red-carded in the dying moments.
The draw for the last eight of the Copa took place on Friday, with Madrid drawn to face Leganes in the first two-legged tie.