The 6-1 result was a statement of intent from the 2008 champion, who outclassed an opponent making only its second ever appearance in the competition.
In the 28th minute, center-back Hesam Nafari scored Iran's 100th goal in tournament history.
Just five minutes later, Iran’s advantage was doubled by Esmaeil Gholizadeh, who calmly dispatched a penalty.
Afghanistan's Hakim Khan Niazi pulled a goal back in the 36th minute.
Kasra Taheri scored Iran’s third goal before the halftime and completed his brace three minutes into the second half.
Gholizadeh made the scoreboard 5-1 in the 51st minute and Reza Ghandipour scored Iran’s sixth goal with one minute remaining.
Iran will play Qatar and South Korea on June 19 and 22 in Group B, respectively.