Stadium: Court 15 Round: 26 Ground: Hardcourt outdoor
| Challenger Cary | 2021/07/20 15:00 | Sam Riffice v Tatsuma Ito | 6-7,6-4,7-5 |
| ITF M25 Tulsa | 2021/06/19 14:00 | Genaro Alberto Olivieri v Sam Riffice | 7-6,7-6 |
| ITF M25 Tulsa | 2021/06/18 14:00 | Gage Brymer v Sam Riffice | 0-6,6-7 |
| ITF M25 Tulsa | 2021/06/17 14:00 | Sam Riffice v Jason Kubler | 6-1,6-4 |
| ITF M25 Tulsa | 2021/06/16 14:00 | Nathan Ponwith v Sam Riffice | 5-7,4-6 |
| Challenger Orlando | 2021/06/12 17:45 | Sam Riffice v Christopher Eubanks | 3-6,6-7 |
| Challenger Orlando | 2021/06/11 17:20 | Ulises Blanch v Sam Riffice | 1-6,5-7 |
| Challenger Orlando | 2021/06/09 14:00 | Roberto Cid Subervi v Sam Riffice | 2-6,2-6 |
| Challenger Braunschweig | 2021/07/04 14:25 | Prajnesh Gunneswaran v Benjamin Hassan | 5-7,4-6 |
| Challenger Porto | 2021/07/01 10:00 | Steven Diez v Prajnesh Gunneswaran | 6-3,1-6,6-4 |
| Challenger Porto | 2021/06/29 16:10 | Mathias Bourgue v Prajnesh Gunneswaran | 2-6,6-3,1-6 |
| Wimbledon | 2021/06/22 13:30 | Arthur Fery v Prajnesh Gunneswaran | 6-1,7-6 |
| French Open | 2021/05/25 08:30 | Oscar Otte v Prajnesh Gunneswaran | 6-2,6-2 |
| ATP Geneva | 2021/05/16 08:30 | Prajnesh Gunneswaran v Mackenzie McDonald | 3-6,6-3,3-6 |
| Challenger Heilbronn | 2021/05/10 15:40 | Alessandro Giannessi v Prajnesh Gunneswaran | 7-6,6-1 |
| ATP Munich | 2021/04/24 12:15 | Prajnesh Gunneswaran v Dennis Novak | 4-6,6-3,5-7 |