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