Mansour Ebrahimzadeh’s charges are level on 16 points with Persepolis but lead on better goal difference.
Igor Castro and Seyed Mohammad Hosseini Farimani gave Zob Ahan a 2-0 lead while Farzad Hatami pulled one back for Saba.
Zob Ahan will host defending Asian champions Korea Republic’s Pohang Steelers in the first leg of their ACL quarter-finals on September 15 before travelling to Pohang for the return leg a week later.
Former leaders Persepolis were held 1-1 by Foolad when Mohammad Nouri’s 36th-minute opener for the Reds was cancelled out by Omid Khouraj in the first half stoppage time.
A 82nd-minute strike from Arash Borhani helped Esteghlal edge past Sepahan 4-3 and go third in the table with 12 points.
Milad Meydavoodi scored a brace while Farhad Majidi scored a goal for Esteghlal while Hashem Beikzadeh opened Sepahan’s account before Milorad Janjus scored a double.
In other matches, Steel Azin lost 1-0 to Teraktor, Shahin beat Rah Ahan 2-0, Malavan defeated Sanat Naft 2-1, Shahrdari went down 4-2 to Peykan, Pas held Saipa 2-2 and Naft played a 1-1 draw with Mes.