Joining four-time champions Arouba in the last-eight on Sunday were last year's runner-up Sohar and Majees.
Sohar was impressive in its 2-0 win over Samail at the Nizwa Sports Complex while Majees, which returned to the Oman Professional League this season, continued its good run as it fought off a gritty challenge from Al Bashayer before winning 2-1 at the Sohar Sports Complex.
Eight-time champions Dhofar was playing another former winner Seeb in a late match on Sunday. The remaining four quarterfinals are on Monday. Record nine-time winners Fanja will locks horns with Oman at the Seeb Sports Stadium while the other matches pit Sur against Bidiya in Sur, Al Musannah against Yanqul at the Sohar Sports Complex and Salalah against Mirbat in a all-Dhofar clubs clash.