Barca were brimming with confidence in the early exchanges against a Verdiblancos side that were struggling to cope with the movement of Alejandro Balde and Ferran Torres, in particular, during the opening exchanges.
However, Manuel Pellegrini’s team nearly added a stunning sucker punch after Willian José played in Luiz Henrique from a tight angle, and the latter's strike went a whisker wide of the far post.
But it was Xavi’s side that broke the deadlock in the 25th minute through Felix, who initially miscontrolled Oriol Romeu's pass before brilliantly recovering and executing a superb finish from a tight angle.
Robert Lewandowski doubled the reigning champions’ lead just past the half-hour mark when Felix showed sublime awareness to let Andreas Christensen’s pass go through his legs, leaving the Polish predator to clinically fire home past Rui Silva.
Marc-Andre ter Stegen was forced into a stunning save to keep the hosts’ two-goal advantage intact after superbly reacting to parry away Jose’s close-range strike to safety in first-half stoppage time.
Pellegrini was forced into changing his goalkeeper ahead of the second half, with Fran Vieites coming on for his Betis debut to replace Silva, along with Ez Abde, who joined this summer from Barcelona, with supposedly a point to prove against his former employers.
Unfortunately for the visitors, that did little to turn the tide of the match, as Torres deservedly added his name to the scoresheet in the 61st minute with a sublime free-kick, which bent brilliantly around the Betis wall and flew into the bottom corner.
It proved to be the 23-year-old’s final act of the game, with Xavi making a triple change that included the introductions of İlkay Gundogan, Raphinha, and Lamine Yamal, as Romeu and Felix also made way.
Raphinha made an immediate impact to add the hosts’ fourth just five minutes later, with the Brazilian taking a touch before expertly tucking home a finish into the bottom corner.
There was still time for a fifth goal through Cancelo, as the Portuguese bamboozled Juan Miranda before delivering a devastating finish.
Pellegrini must be sick of the sight of Barcelona having lost a 25th game to the Catalans as a manager - more than any other club. The Andalusians have now been defeated in each of their last four meetings between the two teams.
Flashscore Man of the Match: Joao Felix (Barcelona)
