The draw for the group stage was held on 6 December 2012, 16:00 UTC+8, at the AFC House in Kuala Lumpur, Malaysia.[2] The 32 teams were drawn into eight groups of four. Teams from the same association could not be drawn into the same group.
The following 32 teams (16 from West Zone, 16 from East Zone) were entered into the group stage draw, which included the 29 automatic qualifiers and the three qualifying play-off winners, whose identity was not known at the time of the draw:
In the group stage, each group was played on a home-and-away round-robin basis. The winners and runners-up of each group advanced to the round of 16.
Tiebreakers[]
The teams are ranked according to points (3 points for a win, 1 point for a tie, 0 points for a loss). If tied on points, tiebreakers are applied in the following order:[1]
Greater number of points obtained in the group matches between the teams concerned
Goal difference resulting from the group matches between the teams concerned
Greater number of goals scored in the group matches between the teams concerned (away goals do not apply)
Goal difference in all the group matches
Greater number of goals scored in all the group matches
Penalty shoot-out if only two teams are involved and they are both on the field of play
Fewer score calculated according to the number of yellow and red cards received in the group matches (1 point for a single yellow card, 3 points for a red card as a consequence of two yellow cards, 3 points for a direct red card, 4 points for a yellow card followed by a direct red card)
Drawing of lots
Groups[]
The matchdays were 26–27 February, 12–13 March, 2–3 April, 9–10 April, 23–24 April, and 30 April–1 May 2013.[3]