Stadium: Court 3 Round: 62
| ITF - Platja D'Aro M15 | 2021/10/11 08:30 | Guy Den Heijer v Aaron Cohen | 4-6,7-6,10-4 |
| ITF - Platja D'Aro M15 | 2021/10/10 08:00 | Guy Den Heijer v Samir Hamza Reguig | 6-1,6-0 |
| ITF - Platja D'Aro M15 | 2021/10/08 12:00 | Guy Den Heijer v Ivan Gakhov | 5-7,4-6 |
| ITF - Platja D'Aro M15 | 2021/10/07 14:25 | Daniel Merida Aguilar v Guy Den Heijer | 3-6,2-6 |
| ITF - Platja D'Aro M15 | 2021/10/06 08:25 | Guy Den Heijer v Alexis Musialek | 5-7,6-4,6-1 |
| UTR Pro Tennis Series - Mulheim | 2021/09/25 13:30 | Colin Sinclair v Guy Den Heijer | 2-6,3-5 |
| UTR Pro Tennis Series - Mulheim | 2021/09/25 08:30 | Mikhail Minakov v Guy Den Heijer | 3-6,6-6 |
| UTR Pro Tennis Series - Mulheim | 2021/09/24 11:00 | Thijmen Loof v Guy Den Heijer | 3-6,2-6 |
| ITF - Platja D'Aro M15 | 2021/10/11 08:30 | Marc Othman Ktiri v Jaime Caldes | 6-4,6-1 |
| ITF - Platja D'Aro M15 | 2021/10/10 11:00 | Egill Sigurdsson v Marc Othman Ktiri | 0-6,0-6 |
| ITF - Platja D'Aro M15 | 2021/10/05 08:30 | Marc Othman Ktiri v Maik Steiner | 6-4,4-6,7-10 |
| ITF - Platja D'Aro M15 | 2021/10/04 11:00 | Franco Emanuel Egea v Marc Othman Ktiri | 6-2,4-6,10-12 |
| ITF - Platja D'Aro M15 | 2021/10/03 12:00 | Nacho Serra Sanchez v Marc Othman Ktiri | 2-6,3-6 |
| ITF - Novi Sad M15 | 2021/07/25 09:30 | Marc Othman Ktiri v Gorazd Srbljak | 4-6,1-6 |
| ATP Mallorca | 2021/06/19 13:45 | Lucas Pouille v Marc Othman Ktiri | 5-7,6-2,6-2 |
| ITF - Antalya M15 | 2021/02/22 07:00 | Dragos Nicolae Madaras v Marc Othman Ktiri | 1-6,6-4,10-6 |