The 46 AFC member associations (excluding the Northern Mariana Islands, which became a full member in December 2020 and are not eligible for this season) are ranked based on their clubs' performance over the last four years in AFC competitions (their national team's FIFA World Rankings no longer considered).
[50] On 11 November 2020, the AFC approved a new calendar for the competition due to the COVID-19 pandemic, where the group stage is played as centralized single round-robin tournament, and the preliminary round, play-off round, and ASEAN Zonal semi-finals and final are played as a single match.
[56] On 9 May 2021, the AFC announced that the South Asia Zone group matches which were originally scheduled between 14 and 20 May would be postponed indefinitely.
[57] On 27 May 2021, the AFC announced that the ASEAN Zone group matches which were originally scheduled between 29 June – 6 July would be postponed indefinitely.
[61] The draw for the group stage was held on 27 January 2021, 14:30 MYT (UTC+8), at the AFC House in Kuala Lumpur, Malaysia.
The West Asia Zonal semi-finals were played over one leg, with the home team determined by the draw mechanism based on which group runners-up qualify.
The three Zonal champions were drawn into two pairings where one club got a bye to the Inter-zone play-off final, which happened for Lee Man.
The home team was determined on a rotation basis, with the match hosted by the winners of the West Asia Zonal final, as in the case of odd-numbered years (Regulations 9.1.2).
[3] Note: Goals scored in the qualifying play-offs are not counted when determining top scorer (Regulations Article 57.4).