Jose Antonio Reyes netted a double and set up one of defender Federico Fazio's two goals for Sevilla in his best performance since returning to his boyhood club last season.
Sevilla could not have asked for a better start at home, jumping ahead just 12 seconds in when Real Betis goalkeeper Adrian San Miguel gifted the ball to Reyes, who blasted it into the top corner.
''It truly was a complete night, for Sevilla, its fans, and for me,'' said Reyes. ''I don't think I have ever scored such a quick goal.''
Its rival rattled, Sevilla poured on the pressure and Fazio met Ivan Ratikic's free kick to turn it beyond the `keeper with a header in the fifth.
Reyes took his second goal in the 32nd by slipping in from behind the flatfooted Nelson Tomar to finish off the rebound of Alvaro Negredo's header that had crashed off the crossbar.
The former Arsenal forward then crossed for Fazio to thump another header just inside the post two minutes before halftime.
Ruben Perez left Betis short-handed in the 62nd after getting two yellow cards in a six-minute span. Striker Ruben Castro pulled one back for Betis four minutes later, before Rakitic capped the demolition in added time.
''I have never seen anything like that first half, it was spectacular,'' said Sevilla coach Michel Gonzalez. ''I take my hat off to all my players.''
Betis remained in sixth place, with Sevilla one point behind level with Valencia.
