In the match, held in Oroumiyeh, northwestern province of West Azarbaijan, the Iranian team, supported by 6,000 noisy fans, edged past Poland 3-2 (25-20, 21-25, 18-25, 25-17, 15-8).
Iran’s Amir Ghafour scored 28 points and Lukasz Kaczmarek had 22 points for Poland.
Iran is scheduled to meet Russia on Sunday at the Ghadir Hall in Oroumiyeh.
The 2019 FIVB Volleyball Men's Nations League is the second edition of the FIVB Volleyball Men's Nations League, an annual international men's volleyball tournament contested by 16 national teams.
The competition is being held between May and July 2019 and the final round will take place in the Credit Union 1 Arena, Chicago, United States.
This is the first edition of the World League or the Nations League to have the Final Round hosted in North America.