Zobahan, coached by Mansour Ebrahimzadeh, did not win the away match on Friday, but will stay atop the standings with three points lead.
The Isfahan-based club has collected 36 points, three more than the second-placed Esteqlal.
In another match of the day, Saba tied 1-1 with Saipa. Karim Ansarifard scored the opener for Saipa by firing home from close range in the 27th minute. Morteza Hashemizadeh equalized for Saba just before the break.
Mes drew 0-0 with Pas, and Naft Abadan beat Shahin 1-0.
Esteqlal's match against Shahrdari Tabriz was called off due to the air pollution in the Iranian capital, Tehran. Azizollah Mohammadi, head of Iran's League Organization, said the match will be held on Saturday.
In other marches of the 18th week of IPL, Tabriz-based club Teraktorsazi defeated Tehran's popular club Persepolis on Thursday to jump to the 5th spot of the table on 28 points.
Persepolis, under Ali Daei, once again showed a poor performance and Karrar Jassim's solo extended the losing streak for the capital-based Reds to four. Persepolis now sits 7th in the IPL table.
Also on Thursday, Siavash Akbarpour scored twice for Steel Azin to see off Foulad 2-1, and the IPL title holder Sepahan moved to the third place in the league table as it drew with Rah Ahan 2-2.