Sasan Ansari found the back of the net in the 16th minute in Ahvaz’s Foolad Arena.
Nassaji midfielder Mahmoud Ghaed Rahmati was shown a red card in the 73rd minute.
In Isfahan, Zob Ahan was held to a goalless draw against Gol Gohar.
Esteghlal finished top as the winner of the first half season, one point above Sepahan.