Igor Kolakovic’s team, who had defeated Canada 3-1 on Friday, will face tournament’s unbeaten team Brazil Saturday night.
Amir Ghafour had 18 points for Iran, while Lincoln Alexander Williams scored 19 points for Australia.
Iran had previously lost to Russia and Egypt in the competition.
The 2019 edition of the FIVB Volleyball Men's World Cup features 12 national teams from the five continental confederations playing in Nagano, Fukuoka and Hiroshima in a round-robin format from October 1 to 15.
The Men's World Cup kicked off for five match days in Fukuoka and Nagano before teams move to Hiroshima for the remaining six match days.