| UTR Pro Tennis Series Atlanta | 2021/07/06 12:00 | Kiger, Mac v Cenoz, Juan Pablo | 1-6,2-6 |
| UTR Pro Tennis Series Atlanta | 2021/07/05 12:00 | Kiger, Mac v Rogers, Andrew | 7-6,4-6,1-6 |
| UTR Pro Tennis Series Nevada | 2021/07/03 16:30 | Hadigian, Eric v Kiger, Mac | 0-0 |
| UTR Pro Tennis Series Nevada | 2021/07/02 18:00 | Kiger, Mac v Joshua Charlton | 6-4,3-6,2-5 |
| UTR Pro Tennis Series Nevada | 2021/07/01 15:00 | Kiger, Mac v Alejandro Quiles | 6-1,6-2 |
| UTR Pro Tennis Series Nevada | 2021/06/30 16:30 | Maxwell McKennon v Kiger, Mac | 6-4,4-6,5-2 |
| UTR Pro Tennis Series Nevada | 2021/06/29 16:30 | Song, Evan v Kiger, Mac | 6-1,5-2 |
| UTR Pro Tennis Series Nevada | 2021/06/27 15:00 | Bailey, Aaron v Kiger, Mac | 6-2,1-0 |
| UTR Pro Tennis Series Atlanta | 2021/07/06 13:30 | Rogers, Andrew v Young, Donald | 1-6,6-4,7-6 |
| UTR Pro Tennis Series Atlanta | 2021/07/04 15:00 | Young, Donald v Cenoz, Juan Pablo | 2-6,6-4,5-1 |
| Orlando, USA | 2021/06/07 17:15 | Polansky, Peter v Young, Donald | 6-2,6-2 |
| Challenger - Little Rock | 2021/06/02 22:55 | Ernesto Escobedo v Young, Donald | 6-3,6-0 |
| Challenger - Tallahassee | 2021/04/20 14:00 | Harrison, Ryan v Young, Donald | 2-6,6-3,6-3 |
| Challenger - Tallahassee | 2021/04/19 15:00 | Young, Donald v Filip Cristian Jianu | 4-6,2-6 |
| Challenger - Tallahassee | 2021/04/18 20:00 | Young, Donald v King, Evan | 6-1,6-2 |
| Challenger - Cleveland | 2021/03/17 23:35 | Alexis Galarneau v Young, Donald | 7-5,7-5 |