Stadium: Court 2 Round: 25 Ground: Clay
| ITF M25 - Ajaccio | 2021/07/08 07:00 | Loris Pourroy v Yannick Mertens | 6-1,4-6,6-3 |
| ITF M25 - Ajaccio | 2021/07/07 10:00 | Pierre Antoine Tailleu v Yannick Mertens | 4-6,4-6 |
| ITF M25 - Bakio | 2021/06/29 15:20 | Yannick Mertens v Christian Harrison | 2-6,6-3,4-6 |
| ITF M15 - Marbella | 2021/05/30 09:00 | Diego F Flores v Yannick Mertens | 2-6,1-6 |
| ITF M15 - Marbella | 2021/05/29 07:55 | Yannick Mertens v Nicolas Alvarez Varona | 1-6,7-5,6-3 |
| ITF M15 - Marbella | 2021/05/28 10:25 | Alejandro Moro Canas v Yannick Mertens | 4-6,5-7 |
| ITF M15 - Marbella | 2021/05/27 09:20 | Maxime Mora v Yannick Mertens | 5-7,0-6 |
| ITF M15 - Marbella | 2021/05/25 09:00 | Francisco Andreu Garcia v Yannick Mertens | 6-7,1-6 |
| ITF M25 - Frankfurt am Main | 2021/08/10 08:20 | Daniel Cukierman v Karlo Cubelic | 2-6,6-4,10-2 |
| ITF M25 - Frankfurt am Main | 2021/08/09 10:50 | Daniel Cukierman v Dominik Kellovsky | 6-2,6-3 |
| ITF M25 - Wetzlar | 2021/08/05 10:40 | David Pichler v Daniel Cukierman | 6-2,6-4 |
| ITF M25 - Wetzlar | 2021/08/04 09:55 | Daniel Cukierman v Lucas Gerch | 6-3,2-6,6-4 |
| ITF M25 - Wetzlar | 2021/08/03 09:00 | Daniel Cukierman v Stepan Pecak | 6-1,6-1 |
| ITF M25 - Wetzlar | 2021/08/02 08:00 | Daniel Cukierman v Tomas Papik | 3-6,7-6,10-4 |
| ITF M25 - Telavi | 2021/07/27 07:30 | Vladyslav Orlov v Daniel Cukierman | 7-5,2-6,7-6 |
| ITF M25 - Marburg | 2021/07/07 12:30 | Daniel Cukierman v Milan Welte | 4-6,4-6 |