In the sixth round of the tournament played on Saturday, Musannah shocked Fanja 3-2 in an entertaining Group B game at the Seeb Sports Stadium, while Sur held Muscat to a 1-1 draw at home in a Group C match and Salalah upset Al Nasr 2-1 in a Group D game at the Saada Sports Complex.
In another Group B match at Seeb, Al Shabab drew with Al Suwaiq 1-1, a result that ended the hopes of both teams to advance to the quarterfinal round.
Musannah and Fanja advanced from their group after both finished with ten points each, but the former topped the table on goal-difference.
Al Nahda had earlier confirmed its place in the quarterfinal stage on November 8 from Group A with a win over Al Khabourah (1-0) to emerge on top with 13 points.
Sohar, despite its latest 0-3 defeat to Saham on the same day, finished second best with ten points to also advance.
In Group C, Muscat became the first club to advance despite its latest draw against Sur.
With nine points, Muscat leads the group with one round to spare. The club, which is back in the Omantel Professional League (OPL), after earning promotion from the first division, won two and drew three games.
Al Arouba, the third team in the group, has two matches remaining and has two points, while Sur is in pole position with six points from five matches.
Dhofar leads Group D with seven points from three matches, while Salalah has five from four games and Al Nasr is at the bottom of the table with four points from five games.
The next round of matches will be held on December 14 with Arouba taking on Muscat at the Sur Sports Stadium, and Salalah locking horns with Dhofar at home.