Stadium: Grandstand Round: 54 Ground: Clay
| Vero Beach, Fl, Singles Qualifying M-ITF-USA-17A | 2021/10/18 16:00 | de Rossi, Marco v Parth Aggarwal | 3-6,6-1,10-2 |
| ITF M15 Naples | 2021/10/13 14:50 | de Rossi, Marco v Liam Draxl | 5-7,0-6 |
| ITF M15 Naples | 2021/10/12 13:30 | de Rossi, Marco v Credit Chaiyarin | 3-6,6-4,10-6 |
| ITF M15 Naples | 2021/10/11 13:30 | de Rossi, Marco v Evan Bynoe | 7-6,6-4 |
| ITF M15 Naples | 2021/10/07 16:10 | de Rossi, Marco v Damien Wenger | 6-4,4-6,4-6 |
| ITF M15 Naples | 2021/10/06 17:25 | Kohen, Alan v de Rossi, Marco | 2-6,4-6 |
| ITF M15 Pescara | 2021/08/16 07:00 | Postay, Alan v de Rossi, Marco | 3-6,6-7 |
| ITF M15 Pescara | 2021/08/15 07:00 | Centi Pizzutilli, Gianluca v de Rossi, Marco | 1-6,1-6 |
| Vero Beach, Fl, Singles Qualifying M-ITF-USA-17A | 2021/10/18 16:00 | Kyle Overmyer v Johnson, Janmagnus | 1-6,0-6 |
| UTR Pro Tennis Series Florida | 2021/01/15 15:30 | Mei, Mesa v Johnson, Janmagnus | 6-1,3-6,5-3 |
| UTR Pro Tennis Series Florida | 2021/01/14 16:00 | Johnson, Janmagnus v Scott, Fletcher | 3-6,6-1,6-2 |
| UTR Pro Tennis Series Florida | 2021/01/11 20:00 | Johnson, Janmagnus v Bruno Kuzuhara | 6-4,4-6,6-7 |
| UTR Pro Tennis Series Florida | 2021/01/10 18:00 | Johnson, Janmagnus v Zlobinsky, Julian | 6-2,5-0 |
| UTR Pro Tennis Series Florida | 2020/12/17 18:00 | Johnson, Janmagnus v Cannon Kingsley | 5-7,4-6 |
| UTR Pro Tennis Series Florida | 2020/12/16 16:00 | Nick Chappell v Johnson, Janmagnus | 2-6,7-6,3-6 |
| UTR Pro Tennis Series Florida | 2020/12/15 20:00 | Evan Bynoe v Johnson, Janmagnus | 1-6,2-5 |