Arne Slot’s side earned a morale boosting 1-0 win over the Spanish giants thanks to a goal from midfielder Alexis Mac Allister.
All the talk ahead of the game was how the home fans would treat former right-back Alexnader-Arnold, 27, upon his return to Anfield.
Liverpool supporters made their feelings known as soon as he walked onto the pitch in the 81st minute as boos and jeers rang out across the ground.
Speaking in an interview with Amazon Prime, Bellingham responded to the criticism of his teammate.
"Obviously, it is one of those things in football,” he said.
“The fans booing isn't a reflection of how they feel about him. I think it is more to give their team the edge and throw him off a little bit. I am sure they're appreciative of what he has done for the club. It is one of those things."