Reza Ma'qouli and Mehdi Chamanara were on target for Foulad, coached by Majid Jalali, and Milad Gharibi scored the only goal for Saipa, under Mohammad Mayelikohan, in the southern Iranian city of Ahvaz on Friday.
Five other matches of the week were also held on the same day while the Iranian table-toppers will meet on Sunday.
In Tehran, Shahin beat Steel Azin 2-0 to make life more difficult for the bottom-rooted star-stud club, and Naft Tehran pummeled Naft Abadan 5-1.
In the other games, Shahrdari defeated Malavan 2-1 in the city of Tabriz, Pas beat Rah Ahan 1-0 in Hamedan, and Peykan posted a 3-2 home win over Saba in Qazvin.
In the standings, Sepahan is leading atop with 58 points; Zob Ahan is second with 53 points, followed by Esteqlal with only one point less.
On Sunday, Sepahan takes on Mes in Kerman, Zob Ahan plays against Persepolis in Isfahan, and Esteqlal is scheduled to meet Teraktorsazi in the Iranian capital, Tehran.