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