As per Regulations Article 15, the tournament starts with a group stage, played in a round robin format. The winners, runners-up and two best third placed teams from each group advance to the knockout stage, in which the teams then compete in single-elimination matches, beginning with the quarter-finals and ending with the final. A third-place deciding match is also contested by the losing semi-finalists. Unlike the two previous editions, there are no consolation matches to decide 5th to 12th place; these placements are instead decided statistically.
Teams
Twelve teams qualified; each domestic league champion from the ten South American nations which are members of CONMEBOL, plus an additional club from the host country and the defending champions.
Each team had to submit a squad of 12 players, including a minimum of two goalkeepers.
Draw
The draw to split the twelve teams into three groups of four took place on 19 November at 19:00 local time in Rio de Janeiro, Brazil at the headquarters of the Brazilian Football Confederation. The draw was conducted based on Regulations Article 16 as follows: Initially, three teams were seeded and assigned to the head of the groups :
to Group B: champions of the host association, Sampaio Corrêa
to Group C: club of the runner-up national association of the 2017 Copa Libertadores, Bella Vista
The remaining nine teams were split into three pots of three based on the final placement of their national association's club in the previous edition of the championship, with the highest seeds placed in Pot 1 down to the lowest placed in Pot 3. From each pot, the first team drawn was placed into Group A, the second team drawn placed into Group B and the final team drawn placed into Group C. Teams from the same association could not be drawn into the same group.
Pot 1
Pot 2
Pot 3
Group stage
The match schedule was revealed on the day of the draw. Each team earns three points for a win in regulation time, two points for a win in extra time, one point for a win in a penalty shoot-out, and no points for a defeat. The top two teams of each group, plus the two best ranked third-placed teams, advance to the quarter-finals. The rankings of teams in each group are determined as follows : If two or more teams are equal on the basis of the above criterion, their rankings are determined as follows: All times are local, BRST
Group A
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Group B
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Group C
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Ranking of third-placed teams
As per Regulations Article 17, it was decided the third place teams would take the following berths in the quarter-final draw:
1st Group A vs 2nd best third place team
1st Group B vs Best third place team
1st Group C vs 2nd Group A
2nd Group B vs 2nd Group C
Knockout stage
The group winners, runners-up and two best third placed teams progressed to the knockout stage to continue to compete for the title.
Argentina
Bolivia
Brazil[|1]
Chile
Colombia
Ecuador
Paraguay
Peru
Uruguay
Venezuela