After winning the first leg 4-0, Barcelona rested key players Lionel Messi, Neymar and Luis Suarez.
They were not needed as Pedro Rodriguez scored a first-half hat-trick while Sergi Roberto and Andres Iniesta also scored before the break.
Adriano, Adama Traore and Sandro Ramirez added further goals, while Galvez Burgos scored a consolation.
Barcelona, who progress with a 12-1 aggregate win, will next play Elche or Valladolid.
In other results, Valencia drew 4-4 with Rayo Vallecano for a 6-5 aggregate victory while Celta Vigo beat Las Palmas to progress 4-3 on aggregate.
Finally, Almeria won 2-1 against Real Betis and go through with a 6-4 aggregate win.
BBC SPORT
