Mohammad Qazi scored the only goal of the match in the 68th minute on Friday afternoon.
The victory moved Mansour Ebrahimzadeh's men to the top of the standings with 33 points after seventeen matches. Sepahan sits in the second place on 31 while Esteqlal is placed third with 27 points.
Esteqlal, coached by Samad Marfavi, is scheduled to play Peykan at Tehran's Azadi Stadium on Saturday afternoon while its archrivals Persepolis, under Croatian Zlatko Kranjcar, faces Sepahan in the Foulad Shahr Stadium in Isfahan.
Friday match results
Zob Ahan 1-0 Malavan
Moqavemat 2-1 Rah Ahan
Teraktorsazi 2-2 Pas
Esteqlal Ahvaz 1-0 Steel Azin
Foulad 0-0 Shahin