| UTR Pro Tennis Series Cancun | 2021/04/06 17:00 | Nathan Oppenheim v Manuel S Montemayor | 2-6,2-6 |
| UTR Pro Tennis Series Manzanillo | 2021/08/10 14:30 | Nathan Oppenheim v Gerardo L Villasenor | 5-7,0-6 |
| UTR Pro Tennis Series Manzanillo | 2021/08/09 18:00 | Nathan Oppenheim v Rafael De Alba | 2-6,2-6 |
| UTR Pro Tennis Series California | 2021/05/26 18:24 | Humberto Lopez v Nathan Oppenheim | 6-1,7-5 |
| UTR Pro Tennis Series California | 2021/05/23 16:30 | Nathan Oppenheim v Hiroki Sakagawa | 1-6,1-6 |
| UTR Pro Tennis Series Cancun | 2021/04/10 17:30 | Clemens Graute v Nathan Oppenheim | 6-4,5-7,6-3 |
| UTR Pro Tennis Series Cancun | 2021/04/08 14:30 | Nathan Oppenheim v Jose Antonio Rodriguez Rodriguez | 6-3,6-2 |
| UTR Pro Tennis Series Cancun | 2021/04/07 19:00 | Nathan Oppenheim v Juan A H Serrano | 0-6,0-6 |
| UTR Pro Tennis Series Cancun | 2021/04/06 17:00 | Nathan Oppenheim v Manuel S Montemayor | 2-6,2-6 |
| UTR Pro Tennis Series Manzanillo | 2021/08/10 14:30 | Rafael De Alba v Manuel S Montemayor | 1-6,2-5 |
| UTR Pro Tennis Series Manzanillo | 2021/08/07 15:00 | Gerardo L Villasenor v Manuel S Montemayor | 3-6,6-4,6-1 |
| UTR Pro Tennis Series Manzanillo | 2021/08/06 15:00 | Emiliano Elizarraras v Manuel S Montemayor | 0-6,1-5 |
| UTR Pro Tennis Series Manzanillo | 2021/08/05 13:00 | Alejandro Hayen v Manuel S Montemayor | 1-6,6-3,0-6 |
| UTR Pro Tennis Series Manzanillo | 2021/08/04 13:00 | Diego Nava v Manuel S Montemayor | 2-6,6-2,2-6 |
| UTR Pro Tennis Series Manzanillo | 2021/08/02 14:30 | Isaac A Arevalo v Manuel S Montemayor | 4-6,3-2 |
| UTR Pro Tennis Series Cancun | 2021/04/10 16:00 | Manuel S Montemayor v Evan Bynoe | 4-6,3-6 |
| UTR Pro Tennis Series Cancun | 2021/04/09 16:00 | Jean-Baptiste Badon v Manuel S Montemayor | 3-6,6-2,6-3 |