2021 Copa Sudamericana group stage

The 2021 Copa Sudamericana group stage was played from 20 April to 27 May 2021. A total of 32 teams competed in the group stage to decide eight of the 16 places in the final stages of the 2021 Copa Sudamericana.

Draw
 The draw for the group stage was held on 9 April 2021, 12:00 PYT (UTC−4), at the CONMEBOL Convention Centre in Luque, Paraguay.

Teams were seeded by their CONMEBOL Clubs ranking as of 1 February 2021 (shown in parentheses), taking into account the following three factors:
 * 1) Performance in the last 10 years, taking into account Copa Libertadores and Copa Sudamericana results in the period 2011–2020.
 * 2) Historical coefficient, taking into account Copa Libertadores and Copa Sudamericana results in the period 1960–2010 and 2002–2010 respectively.
 * 3) Local tournament champion, with bonus points awarded to domestic league champions of the last 10 years.

For the group stage, the 32 teams were drawn into eight groups (Groups A–H) of four containing a team from each of the four pots. Teams from the same association could not be drawn into the same group, excluding the four losers of the Copa Libertadores third stage, which were seeded in Pot 4 and whose identity was not known at the time of the draw, and could be drawn into the same group with another team from the same association.


 * Notes



The following were the four losers of the third stage of the 2021 Copa Libertadores qualifying stages which joined the 12 direct entrants and the 16 Copa Sudamericana first stage winners in the group stage.

Format
 In the group stage, each group is played on a home-and-away round-robin basis. The teams are ranked according to the following criteria: 1. Points (3 points for a win, 1 point for a draw, and 0 points for a loss); 2. Goal difference; 3. Goals scored; 4. Away goals scored; 5. CONMEBOL ranking (Regulations Article 2.4.3).

The winners of each group advanced to the round of 16 of the final stages.

Schedule
The schedule of each matchday was as follows (Regulations Article 2.2.2).