The winners of the tournament automatically qualified for the 2022 AFC Champions League, entering the qualifying play-offs, if they had not qualified through their domestic performance.[4]
Lebanese club Al-Ahed, having won their first AFC Cup title in 2019, were the title holders, since the 2020 edition was cancelled due to the COVID-19 pandemic in Asia after several group stage matches and the title was not awarded. However, Al-Ahed were eliminated by the eventual winners Al-Muharraq in the West Asia Zonal semi-finals.
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).[5] The slots are allocated by the following criteria according to the Entry Manual:[6]
The associations are split into five zones (Article 5.1):
The AFC may reallocate one or more associations to another zone if necessary for sporting reasons.
Excluding the top five associations in each region for AFC Champions League slot allocation, all other associations are eligible to enter the AFC Cup.
The teams from associations ranked 6th, 11th and 12th which are eliminated in the AFC Champions League qualifying play-offs enter the AFC Cup group stage (Article 3.2). The following rules are applied:
The associations ranked 6th in both the West Region and the East Region, while allocated one direct slot in the AFC Cup group stage without taking away any direct slot from other associations, are not ranked in each zone for AFC Cup slot allocation (Article 5.3).[7]
If they advance to the AFC Champions League group stage, the AFC Cup group stage slot is filled by the standby team from their association if such team are available (Article 5.12).
The rules above do not apply to the AFC Champions League title holders and AFC Cup title holders which are allocated AFC Champions League play-off slots should they not qualify for the tournament through domestic performance.
In the West Asia Zone and the ASEAN Zone, there are three groups in the group stage, including 9 direct slots, with the 3 remaining slots filled through qualifying play-offs (Article 5.2). The slots in each zone are distributed as follows:
The associations ranked 1st to 3rd are each allocated two direct slots.
The associations ranked 4th to 6th are each allocated one direct slot and one play-off slot.
The associations ranked 7th or below are each allocated get one play-off slot.
If any zone has an association ranked 6th for AFC Champions League slot allocation, which is allocated one direct slot in the AFC Cup group stage, there are 10 direct slots, with the 2 remaining slots filled through qualifying play-offs.
In the South Asia Zone, the Central Asia Zone, and the East Asia Zone, there is one group in the group stage, including 3 direct slots, with the 1 remaining slot filled through qualifying play-offs (Article 5.2). The slots in each zone are distributed as follows:[8]
The associations ranked 1st to 3rd are each allocated one direct slot and one play-off slot.
The associations ranked 4th or below are each allocated one play-off slot.
If any zone has an association ranked 6th for AFC Champions League slot allocation, which is allocated one direct slot in the AFC Cup group stage, there are 4 direct slots, and to ensure equal opportunity in each zone, another group is added to this zone in the group stage, with the 4 remaining slots filled through qualifying play-offs (Article 5.4.1).
If any zone has at least 7 play-off slots, to ensure equal opportunity in each zone, another group is added to this zone in the group stage, with the 5 remaining slots filled through qualifying play-offs (Article 5.4.2).
If any association with direct slots do not fulfill any one of the AFC Cup criteria, they have all their direct slots converted into play-off slots. The direct slots given up are redistributed to the highest eligible association by the following criteria (Articles 5.7 and 5.8):
For each association, the maximum number of total slots is two (Articles 3.4 and 3.5).
If any association is allocated one additional direct slot, one play-off slot is annulled and not redistributed.
If any association with only play-off slot(s), including those mentioned above, do not fulfill the minimum AFC Cup criteria, the play-off slot(s) are annulled and not redistributed (Articles 5.10 and 5.11).
For each association, the maximum number of total slots is one-third of the total number of eligible teams (excluding foreign teams) in the top division (Article 5.6). If this rule is applied, any direct slots given up are redistributed by the same criteria as mentioned above, and play-off slots are annulled and not redistributed (Article 9.10).
All participating teams must be granted an AFC Champions League or AFC Cup license, and apart from cup winners, finish in the top half of their top division (Articles 7.1 and 9.5). If any association do not have enough teams which satisfy these criteria, any direct slots given up are redistributed by the same criteria as mentioned above, and play-off slots are annulled and not redistributed (Article 9.9).
If any team granted a license refuses to participate, their slot, either direct or play-off, is annulled and not redistributed (Article 9.11).
For the 2021 AFC Cup, the associations are allocated slots according to their association ranking which was published on 29 November 2019,[9][10] which takes into account their performance in the AFC Champions League and the AFC Cup during the period between 2016 and 2019.
Bangladesh (BAN): One of the two teams from Bangladesh which originally entered the AFC Cup, Abahani Limited Dhaka, withdrew from the competition after the draw.[13]
Macau (MAC): The two teams from Macau granted an AFC Cup license, Benfica de Macau and Chao Pak Kei, withdrew from the competition before the draw.[12][14]
Myanmar (MYA): The two teams from Myanmar which originally entered the AFC Cup, Shan United and Hanthawaddy United, withdrew from the competition after the draw.[13]
Philippines (PHI): Philippines were ranked 6th in the East Region for AFC Champions League allocation, and thus were allocated one direct slot in the AFC Cup group stage without taking away any direct slot from other associations. Since Kaya F.C.–Iloilo qualified to the 2021 AFC Champions League through the play-off and no standby club to replace them, Philippines did not participate in the AFC Cup.[16]
Uzbekistan (UZB): Uzbekistan were ranked 6th in the West Region for AFC Champions League allocation, and thus were allocated one direct slot in the AFC Cup group stage without taking away any direct slot from other associations.
Teams in italics will play in the AFC Champions League qualifying play-offs, and will play in the AFC Cup group stage if they fail to advance to the AFC Champions League group stage. Should they advance to the AFC Champions League group stage, they will not play in the AFC Cup, and will be replaced by the standby team from their association if such team are available.
ASEAN Zone (ASZ): On 30 April 2021, the AFC announced that the two teams from Myanmar, Shan United and Hanthawady United, withdrew from the group stage and play-off stage respectively after the draw, due to the state of emergency caused by the 2021 Myanmar coup d'état. As a result, the AFC decided to cancel the two play-off round matches, and promote Persipura Jayapura and the two preliminary stage winners to the group stage.[20] Following the successful qualification of Kaya–Iloilo to AFC Champions League group stage, AFC decided on 6 July 2021 to promote Visakha and Lalenok United to the group stage.[16]
South Asia Zone (SAZ): On 30 April 2021, the AFC decided that Abahani Limited Dhaka were considered to have withdrawn from the preliminary stage after the draw, due to challenges in meeting the extended deadline to host their preliminary round 2 match and also considering the lockdown and travel restrictions due to the COVID-19 pandemic in Bangladesh.[13]
Uzbekistan (UZB):Nasaf, the 2020 Uzbekistan Super League runners-up, were not granted an AFC Champions League license. As a result, AGMK, the second best team granted an AFC Champions League license (2020 Uzbekistan Super League third place), qualified for the 2021 AFC Champions League, and would have played in the AFC Cup had they failed to advance to the AFC Champions League group stage.[11][49] Since AGMK advanced from the AFC Champions League qualifying play-offs to the group stage, Nasaf, which were granted an AFC Cup license and were the standby team from Uzbekistan, replaced AGMK in the AFC Cup group stage.
West Asia Zone (WAZ): On 23 April 2021, the AFC announced that the two teams from Oman, Al-Seeb and Al-Nasr, withdrew from the group stage after the draw, after the suspension of all international and domestic sporting activities due to the COVID-19 pandemic in Oman. As a result, the AFC decided to cancel the play-off round match between Markaz Shabab Al-Am'ari and Al-Kuwait, and promote both teams to the group stage.[15]
Location of teams of the 2021 AFC Cup. Brown: Group A; Red: Group B; Orange: Group C; Yellow: Group D; Pink: Group E; Green: Group F; Blue: Group G; Cyan: Group H; Turquoise: Group I; Purple: Group J; (H) Group stage hosts Qualifying play-offs Withdrawn teams
The schedule of the competition is as follows.[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.[51] On 25 January 2021, the AFC published the schedule of the competition.[52] On 1 March 2021, the AFC announced the hosts for the group stage, except for Group G whose hosts will be decided at a later date.[53] On 27 March 2021, the AFC announced that the West Asia Zone group matches were rescheduled from 23 to 29 May to 21–27 May.[54] On 26 April 2021, the AFC announced that the ASEAN Zone group matches were rescheduled from 22 to 28 June to 29 June – 6 July.[55] On 3 May 2021, the AFC announced that the East Asia Zone group matches were rescheduled from 14 to 20 May to 23–29 June.[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.[58] On 7 July 2021, AFC decided to cancel the matches in ASEAN Zone.[59]
In the qualifying play-offs, each tie was played as a single match. Extra time and penalty shoot-out were used to decide the winner if necessary.[3]
The bracket of the qualifying play-offs for each zone was determined based on each team's association ranking, with the team from the higher-ranked association hosting the match. The one winner of preliminary round 2 (from ASEAN Zone) and one winner of the play-off round (from South Zone) advanced to the group stage to join the 35 direct entrants.[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.[65] The 38 teams were drawn into nine groups of four and one group of three (in the Central Asia Zone): three groups each in the West Asia Zone (Groups A–C) and the ASEAN Zone (Groups G–I), two groups in the Central Asia Zone (Groups E–F), and one group each in the South Asia Zone (Group D) and the East Asia Zone (Group J). For each zone, teams were seeded into four pots and drawn into the relevant positions within each group, based on their association ranking and their seeding within their association, in consideration of technical balance between groups. Teams from the same association in zones with more than one group (West Asia Zone, Central Asia Zone, and ASEAN Zone) could not be drawn into the same group.[66]
In the group stage, each group was played on a single round-robin basis in centralised venues. The following teams advanced to the knockout stage:
The winners of each group and the best runners-up in the West Asia Zone and the ASEAN Zone advanced to the Zonal semi-finals.
The winners of each group in the Central Asia Zone advanced to the Zonal finals.
The teams were ranked according to points (3 points for a win, 1 point for a draw, 0 points for a loss). If tied on points, tiebreakers were applied in the following order (Regulations Article 8.3):[3]
Goals scored in head-to-head matches among tied teams;
Away goals scored in head-to-head matches among tied teams; (not applicable since the matches were played in a centralised venue)
If more than two teams are tied, and after applying all head-to-head criteria above, a subset of teams are still tied, all head-to-head criteria above are reapplied exclusively to this subset of teams;
Goal difference in all group matches;
Goals scored in all group matches;
Penalty shoot-out if only two teams playing each other in the last round of the group are tied;
Disciplinary points (yellow card = 1 point, red card as a result of two yellow cards = 3 points, direct red card = 3 points, yellow card followed by direct red card = 4 points);
^After matches in ASEAN Zone was cancelled, there are only three teams which qualified to the Inter-zone play-off semi-finals, i.e., the winners of the South Asia Zone (Group D), the winners of the East Asia Zone (Group J), and the winners of the Central Zonal final. The three Zonal champions will be drawn into two pairings where one club will get a bye to the Inter-zone play-off final, which happened for Lee Man.
In the knockout stage, the eight teams played a single-elimination tournament. Each tie was played as a single match. Extra time and penalty shoot-out were used to decide the winners if necessary (Regulations Article 9.3 and 10.1).
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. A group winner hosted the match against a group runner-up. If two group winners played each other, one of the group winner (whose group runner-up qualify) hosted the match.[3]
The West Asia and Central Asia Zonal final were played over one leg, with the home team decided by draw. The winners of the West Asia Zonal final advanced to the final, while the winners of the Central Asia Zonal final advanced to the Inter-zone play-off semi-finals.
After matches in ASEAN Zone was cancelled, there were only three teams which qualified to the Inter-zone play-off semi-finals, i.e., the winners of the South Asia Zone (Group D), the winners of the East Asia Zone (Group J), and the winners of the Central Zonal final. 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 matchups and order of legs decided by draw, without any seeding with the winner of Central Zonal Final hosting the match and the winner of South Asia Zone being the away team.[67]
In the Inter-zone play-off final, the two teams which advanced from the Inter-zone play-off semi-finals played each other, with the order of legs determined by the Inter-zone play-off semi-final draw. The winners of the Inter-zone play-off final advanced to the final.
The final was played over one leg, between the winners of the West Asia Zonal final and the winners of the Inter-zone play-off final. 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]
^On 30 April 2021, the AFC decided that Abahani Limited Dhaka were considered to have withdrawn from the preliminary stage after the draw, due to challenges in meeting the extended deadline to host their preliminary round 2 match and also considering the lockdown and travel restrictions due to the COVID-19 pandemic in Bangladesh.[13]
^ abcdOn 30 April 2021, the AFC announced that the two teams from Myanmar, Shan United and Hanthawady United, withdrew from the group stage and play-off stage respectively after the draw, due to the state of emergency caused by the 2021 Myanmar coup d'état. As a result, the AFC decided to cancel the two play-off round matches, and promote Persipura Jayapura and the two preliminary stage winners to the group stage.[13] However, after Kaya–Iloilo secured their qualification for the AFC Champions League group stage and taking into consideration the absence of a standby club from Philippines, on 6 July 2021, the AFC decided to cancel the preliminary stage match between Visakha and Lanelok United and promoted them to Group I.[63] Later, on 7 July 2021, the AFC decided to cancel all matches of the ASEAN Zone, including the preliminary stage match.[64]
^On 23 April 2021, the AFC announced that the two teams from Oman, Al-Seeb and Al-Nasr, withdrew from the group stage after the draw, after the suspension of all international and domestic sporting activities due to the COVID-19 pandemic in Oman. As a result, the AFC decided to cancel the play-off round match between Markaz Shabab Al-Am'ari and Al-Kuwait, and promote both teams to the group stage.[62]
Al-Muharraq (2nd title)
Nasaf
Al-Ahed
Al-Ansar
Al-Faisaly (H)
Altyn Asyr
Ahal
Maziya (H)
Eagles
Eastern (H)
Lion City Sailors (H)
Geylang International (H)
Blue: Group G; 
Sri Lanka Police
Thimphu City
Kasuka
Lalenok United
Al-Kuwait
Al-Ahed
Al-Wahda
Al-Salt (H)
Ahal
Dordoi (H)
Ravshan Kulob
Hanoi
Winners of ASEAN 2.1
Kedah Darul Aman
Lion City Sailors
Lee Man (H)
Tainan City
Athletic 220
74'
Ahmed Akaïchi
Gil
Ronald Ngah
Andrija Kaluđerović
José Ángel
Chen Jui-chieh
Roy Krishna
