Iran, who qualified for the last World Cup in Brazil, topped the group with 20 points after beating runner-up Oman 2-0 in Tehran’s Azadi Stadium thanks to a Sardar Azmoun brace.
Azmoun found the back of the net with two headers in the 16th and 23rd minutes.
The draw for the third round, where the 12 teams will be split into two groups and the top two from each advance to Russia 2018, will take place next month.