Stadium: Court 7 Round: 62 Ground: Clay
| ITF M15 Norman | 2023/10/26 16:25 | Justin Schlageter v Duarte Vale | 2-6,1-6 |
| ITF M15 Norman | 2023/10/25 21:05 | Justin Schlageter v Fons Van Sambeek | 7-6,4-6,7-5 |
| ITF M15 Uberlingen | 2023/08/15 15:25 | David Fix v Justin Schlageter | 7-5,6-3 |
| ITF M15 Norman | 2022/10/26 17:00 | Justin Schlageter v Tyler Zink | 7-6,3-6,4-6 |
| ITF M15 Bad Salzdetfurth | 2019/10/07 12:55 | Justin Schlageter v Lasse Muscheites | 4-6,5-7 |
| ITF Germany F14 | 2018/10/03 14:20 | Justin Schlageter v Christian Seraphim | 1-6,6-7 |
| Challenger Pullach Qual | 2018/08/04 13:10 | Justin Schlageter v Fabrizio Ornago | 4-6,6-7 |
| ITF Croatia F2 | 2018/03/10 09:00 | Karlo Kajin v Justin Schlageter | 3-6,6-2,6-4 |
| ITF M15 Rovinj | 2024/03/11 08:30 | Ruben Hartig v Lorenzo Vatteroni | 1-6,0-6 |
| ITF M15 Porec | 2024/03/03 10:00 | Stepan Baum v Ruben Hartig | 6-1,1-6,12-10 |
| ITF M25 Hammamet | 2024/02/12 08:30 | Daniel Bagnolini v Ruben Hartig | 6-3,6-0 |
| ITF M15 Antalya | 2023/12/17 07:00 | Hien Q H Pham v Ruben Hartig | 6-4,7-6 |
| ITF M15 Antalya | 2023/12/10 07:00 | Pablo Roche Alcaya v Ruben Hartig | 7-6,6-3 |
| German Championship | 2023/12/03 16:00 | Sebastian Gampert v Ruben Hartig | 6-2,6-3 |
| ITF M25 Monastir | 2023/11/12 08:00 | Ruben Hartig v Teymuraz Gabashvili | 2-6,0-6 |
| ITF M25 Monastir | 2023/11/06 09:30 | Toby Martin v Ruben Hartig | 6-1,6-1 |