If the aggregate score was level, the second-leg match would go straight to the penalty shoot-out to determine the winners.
[2] The draw for the round of 16 was held on 22 June 2021, 16:00 at CBF headquarters in Rio de Janeiro.
[3] The 16 qualified teams were drawn in a single group (CBF ranking shown in parentheses).
The draw for the quarter-finals was held on 6 August 2021, 15:00 at CBF headquarters in Rio de Janeiro.
The draw to determine the home-and-away teams for both legs was held on 22 September 2021, 15:00 at CBF headquarters in Rio de Janeiro.
The draw to determine the home-and-away teams for both legs was held on 4 November 2021, 15:00 at CBF headquarters in Rio de Janeiro.