Stadium: Court 22 Round: 25 Ground: Clay
| ITF M15 - Lambermont | 2022/08/27 11:00 | Stijn Slump v Marcel Zielinski | 7-6,6-3 |
| ITF M15 - Eindhoven | 2022/08/16 12:05 | Stijn Slump v Marcel Zielinski | 6-7,4-6 |
| ITF M15 - Telde | 2024/04/11 12:35 | Kane Bonsach Ganley v Marcel Zielinski | 7-6,7-6 |
| ITF M15 - Telde | 2024/04/10 14:35 | Benjamin Pietri v Marcel Zielinski | 4-6,1-6 |
| ITF M15 - Antalya | 2024/03/28 07:00 | Marcel Zielinski v Jiri Barnat | 2-6,0-6 |
| ITF M15 - Antalya | 2024/03/27 08:50 | Marcel Zielinski v John Sperle | 7-5,6-4 |
| ITF M15 - Antalya | 2024/03/21 07:00 | Marcel Zielinski v Ioan Alexandru Chirita | 6-7,1-6 |
| ITF M15 - Antalya | 2024/03/13 07:00 | Marcel Zielinski v Jordi Garcia Mestre | 4-6,1-6 |
| ITF M25 - Hammamet | 2024/02/14 13:30 | Daniel Bagnolini v Marcel Zielinski | 6-4,6-3 |
| ITF M25 - Hammamet | 2024/02/06 13:50 | Oscar Jose Gutierrez v Marcel Zielinski | 6-3,6-0 |
| ITF M15 - Antalya | 2024/04/17 08:35 | Kokoro Isomura v Stijn Slump | 3-6,6-4,6-0 |
| ITF M15 - Antalya | 2024/03/30 07:30 | Nicolai Budkov Kjaer v Stijn Slump | 6-3,6-0 |
| ITF M15 - Antalya | 2024/03/29 08:30 | Stijn Slump v Atakan Karahan | 7-6,6-2 |
| ITF M15 - Antalya | 2024/03/28 09:10 | Vlad Andrei Dancu v Stijn Slump | 6-3,3-6,4-6 |
| ITF M15 - Antalya | 2024/03/27 14:25 | Stijn Slump v Gorazd Srbljak | 6-7,6-3,6-1 |
| ITF M15 - Antalya | 2024/03/26 09:00 | Stijn Slump v Ioan Alexandru Chirita | 6-2,6-0 |
| ITF M15 - Antalya | 2024/03/25 06:55 | Stijn Slump v Sergio Badini | 6-3,6-2 |
| ITF M15 - Antalya | 2024/03/24 07:00 | Stijn Slump v Michel Hopp | 6-7,6-4,10-8 |