Stadium: Cancha 7 Round: 26 Ground: Hardcourt outdoor
| ITF M15 East Lansing | 2021/11/16 15:00 | Osgar O'Hoisin v Niroop Vallabhaneni | 6-1,1-6,5-10 |
| ITF M15 Ithaca | 2021/11/04 16:20 | Osgar O'Hoisin v Evan Bynoe | 3-6,6-4,3-6 |
| ITF M15 Ithaca | 2021/11/03 16:40 | Evan Zhu v Osgar O'Hoisin | 6-7,3-6 |
| ITF M15 Cancun | 2021/10/19 14:00 | Juan Sebastian Osorio v Osgar O'Hoisin | 3-6,7-5,6-4 |
| ITF M15 Cancun | 2021/09/27 14:30 | Jack Gibbens v Osgar O'Hoisin | 3-6,7-6,7-10 |
| ITF M15 Cancun | 2021/09/26 15:00 | Babji Siva Atturu v Osgar O'Hoisin | 1-6,0-6 |
| ITF M15 Cancun | 2021/09/25 18:05 | Osgar O'Hoisin v Gerardo L Villasenor | 4-6,2-6 |
| ITF M15 Cancun | 2021/09/24 19:30 | Osgar O'Hoisin v Leonardo Civita-Telles | 7-5,2-6,7-5 |
| ITF M15 East Lansing | 2021/11/18 18:00 | Alexandre Rotsaert v Colin Sinclair | 5-7,6-4,2-6 |
| ITF M15 East Lansing | 2021/11/17 20:45 | Nico Mostardi v Colin Sinclair | 3-6,4-6 |
| ITF M15 Ithaca | 2021/11/04 16:45 | Colin Sinclair v Vasil Kirkov | 3-6,4-6 |
| ITF M15 Ithaca | 2021/11/03 17:55 | Michael Zheng v Colin Sinclair | 0-6,2-6 |
| ITF M15 Tallahassee | 2021/10/27 14:00 | Colin Sinclair v Ryan Shane | 6-3,3-6,6-7 |
| ITF M15 Ithaca | 2021/10/05 16:00 | Taha Baadi v Colin Sinclair | 7-6,7-5 |
| ITF M25 Budapest | 2021/09/28 10:45 | Pawel Juszczak v Colin Sinclair | 6-2,7-6 |
| UTR Pro Tennis Series Mulheim | 2021/09/25 13:30 | Colin Sinclair v Guy Den Heijer | 2-6,3-5 |