Esteghlal's 3-2 win over Pas Hamedan had seen them go top yesterday, but goals from Mehdi Rajabzadeh and Mohamadreza Khalatbari put 2010 AFC Champions League finalists Zob Ahan two points clear.
Meanwhile, Mes remain in third after a goal in each half from Luciano gave them a 2-0 win over Rah Ahan.
Fourth-placed Sepahan eased to a 4-1 win at home to Saipa, with Ibrahima Toure scoring a hat-trick. The Senegalese striker opened the scoring in the 43rd minute before adding a second less than a minute later. Moharram Navidkia made it 3-0 before Toure scored his third with 13 minutes remaining. Sajjad Shahabzadeh scored a 90th-minute consolation for Saipa.
Perspolis dropped to fifth as they suffered a 3-0 defeat at Peykan with Alireza Abbasfard, Meysam Rezapour and Jahangir Asgari scoring for the hosts.
In other games, Naft Tehran drew 2-2 with Shahin FC. Mansour Tanhaei put Shahin ahead after three minutes before Mohammad Mehrazma equalised just before the half hour. Alireza Ezati then put Naft ahead in the 64th minute only for Mehdi Taromi to secure a point for Shahin six minutes from time.
Finally, Teraktor Sazi beat Sanat Naft 3-1. Ali Alizadeh opened the scoring just before the hour and a 72nd-minute Farad Ale Khamis own goal made it 2-0. Roohollah Arab pulled one back in the 84th minute but Mohammad Ebrahimi made the points safe with a last-minute goal.