However, Arouba lost its penultimate game 2-3 to Sur on Saturday, to stay on 49 points with a game remaining.
Sur is second with 43 points and leads Fanja by two points with the latter having played a game less.
Arouba has a chance to exact revenge and clinch a domestic double when it takes on Sur in the His Majesty's Cup final in Sur on May 22.
Also on Saturday, Seeb's goalless draw against Sohar confirmed its relegation to the first division league next season.
Seeb has only 17 points and a game left. The other two teams fighting to save relegation are Bausher and former champion Al Nahda, which was docked six points earlier in the season on disciplinary grounds.
On Friday, Muscat and Salalah finished as top two teams in the first division league to earn promotion into the OPL.