Yuki Ishikawa and Shahram Mahmoudi were joint top scorers for Iran and Japan respectively with 20 apiece.
Iran will play Australia on September 21.
Team Melli has lost to Argentina, Poland, Russia, Italy and USA so far and defeated Tunisia, Venezuela and Japan.
The tournament is a qualification process for the 2016 Summer Olympics in Rio de Janeiro, Brazil.
The top two teams will qualify for the Olympics and join Brazil as it has already secured a berth as the host country.
Iran is mathematically out of the running for a top two finish.