The in-form Blaugrana stunned the Partenopei at their own backyard to advance to the last 16 of the competition 5-3 on aggregate, having drawn the first leg 1-1 in Spain last week.
Barcelona dominated possession throughout and raced into a 3-1 lead by the break thanks to goals from Jordi Alba, Frenkie de Jong and Gerard Pique while Pierre-Emerick Aubameyang also got in on the act in the second half.
"Perhaps, this was the most complete performance of our season," the head coach said. "We wanted to dominate and we did.
"I'm happy about the effort we put in and with the football we played. The result is fair.
"I am very happy for the players and this is the way forward. We are on the right road.
"We pressed well, high up, whenever we lost the ball – just like we did at home.
"Napoli pressed high up and spaces were available in behind them. From defending a corner, we made a textbook counter-attack. We took advantage of our fast players.
"We understood how to create and use a 'free man'. I'm very happy for the team."
Barcelona will find out their opponents in the next round later on Friday.
