Iran handball team defeated Japan 37-32 at the Seo-Suwon Chilbo Gymnasium in Suwon, South Korea on Saturday.
Team Melli had defeated Uzbekistan 37-18 in its opening Group A match on Friday.
Iran will meet the Group D second finisher on Monday.
The 2018 Asian Men's Handball Championship is the 18th edition of the championship held under the aegis of Asian Handball Federation.
The championship is being held at Suwon, South Korea from January 18 to 28, 2018.
It acts as the Asian qualifying tournament for the 2019 World Men's Handball Championship. Australia, New Zealand and Bangladesh participated for the first time.