[5] Due to the Russian invasion of Ukraine which commenced in February 2022, the final was eventually moved to Saint-Denis.

Chelsea were the defending champions, but they were eliminated in the quarter-finals by eventual winners Real Madrid.

The third qualifying round second legs were only played on a Tuesday due to the 2021 UEFA Super Cup on the following Wednesday.

[19] The preliminary round matches, which consisted of two semi-finals on 22 June 2021 and the final on 25 June 2021, were originally to be played at Gundadalur, Tórshavn in the Faroe Islands,[20] but were moved due to restrictions related to the COVID-19 pandemic in the Faroe Islands.

The losers of the semi-finals and final were transferred to the Europa Conference League Champions Path second qualifying round.

The losers were transferred to the Europa Conference League Champions Path second qualifying round.

In the knockout phase, teams played against each other over two legs on a home-and-away basis, except for the one-match final.

In the following tie, Liverpool were mistakenly included in the draw for Atlético Madrid's opponent (both were in Group B), while Manchester United were incorrectly excluded.

[37] UEFA and the national associations announced that if such a league were to be established, its participants would be banned from playing in international and domestic competitions.

[38] Later that same day, English clubs (Arsenal, Chelsea, Liverpool, Manchester City, Manchester United and Tottenham Hotspur), Italian clubs (Inter Milan, Juventus and Milan) and Spanish clubs (Atlético Madrid, Barcelona and Real Madrid) announced the establishment of the Super League, putting them at risk of being banned.

[39] On 20 April 2021, Arsenal,[40] Liverpool,[41] Manchester City,[42] Manchester United[43] and Tottenham Hotspur[44] withdrew after the Football Association threatened to ban participating clubs from domestic football,[45] whilst Chelsea withdrew some hours later.

[48] The Super League suspended its operations,[49] with the case to be taken by the Court of Justice of the European Union (CJEU) to establish whether UEFA and FIFA have the exclusive right to organise competitions.

[50] On 7 June 2021, the Swiss Federal Department of Justice and Police notified UEFA and FIFA of the Spanish precautionary measure – which had earlier issued an injunction against UEFA and FIFA and referred a cuestión preliminar (English: preliminary question) to the CJEU on whether UEFA and FIFA have violated articles 101 and 102 of the TFEU[51] – ruling that neither governing body could not execute sanctions against Super League clubs.

[52] On 15 June 2021, it was officially confirmed that the remaining three clubs (Barcelona, Juventus and Real Madrid) – which did not sign the Commitment Declaration of the sanctioned other nine clubs[53] and filed a new motion to scrap the agreement UEFA signed with those nine clubs[50] – were admitted to the 2021–22 UEFA Champions League, pending the disciplinary proceedings UEFA opened against them but which were suspended after the Swiss notification.