Though they managed to win 2-1, the visitors finished the first-half a goal down - and having managed just one shot on goal.
"What are we doing?!" was one of the first cries from the away dressing room heard within earshot. "What are we playing?!"
The question sparked furious responses as senior players voiced their frustrations, says AS.
French trio Antoine Griezmann, Samuel Umtiti and Ousmane Dembele could be heard arguing with eachother before Gerard Pique and Luis Suarez took charge. The pair moved to rally the players, declaring: "C'mon. C'mon. Let's play as we know."
After the break, Barca fought back to win 2-1 thanks to goals from Suarez and Arturo Vidal.