Stadium: Court 7 Round: 54 Ground: Clay
| UTR Pro Hilversum | 2023/06/06 06:00 | Guy Den Heijer v Victor Sklenka | 7-6,4-6,5-3 |
| UTR Pro Hilversum | 2023/06/05 07:30 | Guy Den Heijer v Ivan Sergeyev | 0-6,2-6 |
| ITF M15 Antalya | 2023/04/30 07:00 | Guy Den Heijer v Juan Manuel La Serna | 6-7,1-6 |
| ITF M15 Antalya | 2023/04/02 07:00 | Guy Den Heijer v Niels Visker | 1-6,6-4,3-10 |
| ITF M25 Portimao | 2023/03/14 11:00 | Guy Den Heijer v Mikel Martinez | 1-6,2-6 |
| ITF M25 Portimao | 2023/03/13 15:35 | Guy Den Heijer v Miguel Pereira Lopes | 6-1,6-3 |
| ITF M25 Quinta Do Lago | 2023/03/09 17:20 | Jesper De Jong v Guy Den Heijer | 6-3,6-1 |
| ITF M25 Quinta Do Lago | 2023/03/09 13:30 | Sean Hodkin v Guy Den Heijer | 4-6,4-6 |