The opening day featured nine matches. Record nine-time champions Fanja sailed into the last-16 with an easy 3-1 win over Al Salam at the Sultan Qaboos Sports Complex (SQSC).
However, it was the Batinah derby that stole the limelight as last year's surprise runner-up Sohar edged past Saham 3-2 at a packed Sohar Sports Complex.
Bidiyah sent Al Shabab crashing out with a narrow 1-0 win on a day when another OPL club, Al Rustaq, also made its exit, losing to Salalah Club 0-3.
Another Salalah region club, Mirbat, was too strong for Al Mudhaibi, winning 4-0 while former champions Sur scraped past Diba 1-0. Also advancing to the round-of-16, which is also a knockout stage, were Bahla, Samail and Al Mussanah, all the three clubs recording a similar 1-0 scoreline, against Jalan, Quriyat and Al Hamra respectively.
On Wednesday, defending champion Al Nasr will begin its title defence against three-time champion Seeb while eight-time winners Dhofar will take on former winner Muscat in an exciting clash at the SQSC.
Also in action will be former multiple title-winners, Al Suwaiq (three), Al Arouba (four), Ahli-Sidab (five) and Oman (two).
The knockout round-of-16 will be held on October 7. The quarterfinals will witness home and away legs to be played on November 6 and December 4 while the double-leg semis are scheduled to be held on March 16 and April 10 next year. The final is expected to be held in April.
Tuesday's results (round-of-32): Jalan 0 Bahla 1, Fanja 3 Al Salam 1, Quriyat 0 Samail 1, Bidiyah 1 Al Shabab 0, Al Mudhaibi 0 Mirbat 4, Al Hamra 0 Al Mussanah 1, Diba 0 Sur 1, Salalah 3 Al Rustaq 0, Saham 2 Sohar 3.
Wednesday's fixtures: Al Arouba vs Ahli-Sidab, Muscat vs Dhofar, Seeb vs Al Nasr, Al Wasta vs Yanqul, Majees vs Al Nahda, Nizwa vs Oman, Al Bashayer vs Al Suwaiq.