The clubs were ranked according to points and tie breakers were in the following order: The seven group winners along with the defending champion advanced to the quarter-finals.
The games were conducted in 2 legs, home and away, and the aggregate score decided the match winner.
If the aggregate score couldn't produce a winner, "away goals rule" was used.
If still tied, clubs played extra time, where "away goals rule" still applied.
For this year the competition was restricted to clubs from countries considered 'mature' in the 'Vision Asia' paper of AFC President Mohamed Bin Hammam, with clubs from 'developing' countries entering the newly created AFC Cup and 'emerging' nations to enter the AFC President's Cup from 2005 onwards.