With a major presence of teams with a Back 4 defense, the Brazilian and Argentinian clubs are the most represented clubs in the list of the Top Performing CBs of the 2021 Libertadores.
| Player | Rating | Defense | Minutes Played | Team |
| Héctor Martínez | 7.77 | Back 4 | 630 | River Plate |
| Leo Ortiz | 7.62 | Back 4 | 450 | Bragantino |
| Marcos Rojo | 7.62 | Back 4 | 300 | Boca Juniors |
| Paulo Díaz | 7.59 | Back 4 | 630 | River Plate |
| Omar Merlo | 7.42 | Back 4 | 450 | Sporting Cristal |
| Léo Pereira | 7.41 | Back 4 | 521 | Flamengo |
| Rafael Marcelo Delgado | 7.39 | Back 5 | 360 | Colón |
| Carlos Izquierdoz | 7.36 | Back 4 | 390 | Boca Juniors |
| Guilherme Tinga | 7.22 | Back 5 | 270 | Fortaleza |
| Raul Bicalho | 7.14 | Back 4 | 450 | Corinthians |
| David Luiz | 7.10 | Back 4 | 720 | Flamengo |
| Agustín Rogel | 7.03 | Back 4 | 270 | Estudiantes |
| Benjamín Kuscevic | 7.02 | Back 4 | 360 | Palmeiras |
| Agustín Rogel | 7.02 | Back 5 | 540 | Estudiantes |
| João Victor | 7.01 | Back 4 | 360 | Corinthians |
Conditions for the presented data:
– Minimum minutes played in the season: 270 minutes (equivalent to 3 full games) per type of defense played (Back 4 or Back 5);
– Libertadores Qualifying Round data excluded;
Data from FBref.