Dejagah and Co. defeated Bahrain 2-0 in their Asian Cup opener in Melbourne on Sunday, with the vast majority of the 17,712-strong crowd decked out in Iran's colours of white, green and red.
The fans generated an exhilarating atmosphere at AAMI Park, which Dejagah likened to playing in Iran's capital Tehran, and the former Fulham midfielder urged Sydney's Iranian community to provide similar support.
"Of course, it's like a 12th man," he said.
"I hope the next game it's the same and we can do them proud."
Iran will hope to capitalise on Qatar's poor start to the Asian Cup with Djamel Belmadi's men having collapsed to lose 4-1 to United Arab Emirates in Canberra.
Khalfan Ibrahim gave Qatar the lead in Australia's capital city after 21 minutes but braces to Ahmed Khalil and Ali Ahmed Mabkhout saw UAE crush the 2014 Gulf Cup champions.
Qatar have only reached the quarter-finals twice in eight Asian Cup appearances and will be eliminated if they lose to Iran.
Queiroz's Persians, by comparison, are looking to continue their country's strong continental record that includes three titles (1968, 1972, 1976).
Iran were impressive against Bahrain with Dejagah, Reza Ghoochannejhad, Ehsan Hajsafi and Masoud Shojaei providing a fine combination of power and skill in the final third, while Queiroz's men also looked solid in defence.
Somewhat surprisingly, Qatar's back four struggled against UAE, as Belmadi's team had won the Gulf Cup due to their tight defensive set-up.
Qatar drew their three group matches in Saudi Arabia, including scoreless stalemates against Yemen and Bahrain, before growing in confidence in the knockout stage, defeating Oman 3-1 in the semi-finals and the hosts 2-1 to lift the trophy.
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