In Tehran, Esteghlal beat Nassaji courtesy of goals from Armin Sohrabian, Mohammad Mehdi Janmaleki (own goal), Armin Ramezani and Abolfazl Jalali.
Sepahan, earlier in the day, had defeated Havadar 5-0 in Tehran to stay neck and neck in title race. Ramin Rezaeian, Shariyar Moghanlou (two goals), Kaveh Rezaei and Reza Asadi scored for the visiting team.
Persepolis, meanwhile, was held to a 2-2 draw by struggling Esteghlal Khuzestan in Ahvaz. Javad Aghaeipour scored twice for Esteghlal Khuzestan and Hossein Kanaani and Nabil Bahoui were on target for Persepolis.
Matchweek 13:
*Esteghlal 4-0 Nassaji
*Havadar 0-5 Sepahan
*Esteghlal Khuzestan 2-2 Persepolis
*Shams Azar 0-0 Sanat Naft
*Aluminum 0-0 Gol Gohar
*Zob Ahan 0-0 Foolad