Captain Javad Nekounam
led the way with a hat-trick, two of which came from the penalty spot,
while Standard Liege forward Reza Ghoochannejhad netted the other two
In the same group Kuwait saw off Thailand 3-1 in Bangkok.
Former champion Saudi Arabia got its qualifying campaign off to a winning start with a 2-1 triumph over China.
Saudi Arabia, which has reached the final in six of the last eight editions and won the event in 1984, 1988 and 1996, claimed the points in new coach Juan Ramon Lopez Caro's first competitive game since replacing Frank Rijkaard thanks to Naif Hazazi's 77th-minute winner.
Joining the Saudis on three points in a tough-looking Group C was 2007 champion Iraq, which beat Indonesia 1-0 courtesy of a second-half goal from Younus Mahmoud in Dubai.
Uzbekistan, which is the top-ranked team in qualifying with Asian heavyweights Japan, Korea DPR, Korea Republic and host nation Australia already through to the finals, was held to a goalless home draw by Hong Kong in its opener despite playing against 10 men for over half-an-hour.
That left it third in Group E, with United Arab Emirates leading the way after its 2-1 away win over Vietnam.
In Group A, Jordan started its campaign with a convincing 4-0 win over Singapore while Oman defeated Syria 1-0.
Bahrain and Qatar share the lead in Group D after both recorded 2-0 triumphs, beating Yemen and Malaysia respectively.
The top two nations from each group will qualify for the 2015 Asian Cup with the best third-placed team from all groups also earning a ticket to Australia.