Neymar scored his second in the early stages of the second period, before the Brazilian completed his hat-trick with 30 minutes remaining.
Here, Sports Mole dissects the 90 minutes of action between the two European rivals.
On target: 18
On target: 5
Was the result fair?
In truth, Barcelona could and perhaps should have reached double figures this evening. Celtic had some positive moments in the opening 20 minutes or so, but struggled when the second goal went in. The Scottish champions have made it difficult for Barcelona in fixtures over the last couple of seasons, but that was simply not the case this evening. The scoreline certainly does not flatter the Catalan outfit.
Barca boss Gerardo Martino has faced criticism this season for a perceived change of playing style. Well, if he continues to win football matches in this manner, the critics will soon fade. The Spanish outfit did not need to be at their best this evening, but still managed to score six times, which is a worry for the rest of Europe. Tougher tests are ahead for the La Liga side, but it was a slick, impressive performance.
The Scottish champions had only pride to play for this evening and as harsh as it sounds, they let their manager and supporters down. They were never going to match the ability of their opponents, but there was a lack of willingness to get close to Barcelona in midfield areas. They almost took a point from the Camp Nou last season, but they were utterly outclassed this time around. It is back to the drawing board for Neil Lennon as he prepares for another European challenge next season.
Sports Mole's man of the match
Neymar: In truth, this was not a difficult decision. The Brazilian forward was just sensational this evening as he struck a hat-trick in the Camp Nou. Aside from his goals, the former Santos striker was a constant menace with his pace and movement. It was a dream night for the 21-year-old.
Neymar looked to be moments away from scoring his fourth after 66 minutes when he rounded Fraser Forster in the Celtic goal, but Pedro got in the Brazilian's way at the vital moment, before striking straight at defender Virgil van Dijk from close range. It was an incredible mix-up in the home side's attack.
Sergey Karasev had a couple of penalty shouts to deal with in the first period, but the Russian got both decisions correct. In truth, it was a relatively straightforward night for the official, with neither manager expected to have any complaints about his performance.
Barcelona: The Catalan outfit will attempt to consolidate first spot in La Liga when they host Villarreal on Saturday evening.
Celtic: The Scottish champions also resume domestic action at home to Hibernian on Saturday afternoon.