| Argentina (4) |
|---|
| Delbonis, Federico | | Mayer, Leonardo | | Pella, Guido | | Schwartzman, Diego |
| | Austria (2) |
|---|
| Haider-Maurer, Andreas | | Thiem, Dominic |
| | |
| Brasil (1) |
|---|
| Dutra Silva, Rogerio |
| | Bulgaria (1) |
|---|
| Dimitrov, Grigor |
| | |
| France (4) |
|---|
| Mannarino, Adrian | | Moutet, Corentin | | Paire, Benoit | | Simon, Gilles |
| | Germany (2) |
|---|
| Gojowczyk, Peter | | Zverev, Mischa |
| | Greece (1) |
|---|
| Tsitsipas, Stefano |
| | Japan (2) |
|---|
| Nishikori, Kei | | Sugita, Yuichi |
|
| Kazakhstan (1) |
|---|
| Kukushkin, Mikhail |
| | Mexico (1) |
|---|
| Escobedo, Ernesto |
| | | Russia (3) |
|---|
| Khachanov, Karen | | Rublev, Andrey | | Vatutin, Alexey |
|
| Serbia (2) |
|---|
| Djokovic, Novak | | Lajovic, Dusan |
| | Slovakia (2) |
|---|
| Klizan, Martin | | Kovalik, Jozef |
| | South Korea (1) |
|---|
| Chung, Hyeon |
| | Spain (14) |
|---|
| Andujar, Pablo | | Bautista Agut, Roberto | | Carballes Baena, Roberto | | Carreno Busta, Pablo | | Garcia-Lopez, Guillermo | | Granollers, Marcel | | Lopez, Feliciano | | Martinez, Pedro | | Munar, Jaume | | Nadal, Rafael | | Ojeda Lara, Ricardo | | Ramos-Vinolas, Albert | | Robredo, Tommy | | Verdasco, Fernando |
|
| | United States (3) |
|---|
| Donaldson, Jared | | Fratangelo, Bjorn | | Sandgren, Tennys |
| |