Stadium: ACTIVE+Logistics-C6 Round: 25 Ground: Clay
| ITF - M25 Trier | 2021/08/24 11:00 | Milan Welte v Tim Handel | 6-2,1-6,6-7 |
| ITF - M25 Ueberlingen | 2021/08/19 10:35 | Louis Wessels v Milan Welte | 6-4,6-3 |
| ITF - M25 Ueberlingen | 2021/08/18 14:10 | Milan Welte v Constantin Bittoun Kouzmine | 6-4,6-0 |
| ITF - M25 Frankfurt am Main | 2021/08/09 14:10 | Milan Welte v Taiyo Yamanaka | 6-7,4-6 |
| ITF - M15 Parnu | 2021/08/04 09:20 | Vladimir Ivanov v Milan Welte | 7-5,1-6,6-3 |
| ITF - M25 Marburg | 2021/07/09 12:00 | Ryan Nijboer v Milan Welte | 4-6,6-3,6-1 |
| ITF - M25 Marburg | 2021/07/08 08:55 | Milan Welte v Neo Niedner | 6-2,6-1 |
| ITF - M25 Marburg | 2021/07/07 12:30 | Daniel Cukierman v Milan Welte | 4-6,4-6 |
| ITF - M25 Ueberlingen | 2021/08/19 10:00 | Niklas Schell v Eduard Esteve Lobato | 6-7,1-6 |
| ITF - M25 Ueberlingen | 2021/08/18 09:30 | Niklas Schell v Florian Broska | 3-6,6-3,6-3 |
| ITF - M25 Frankfurt am Main | 2021/08/10 10:30 | Taiyo Yamanaka v Niklas Schell | 6-1,6-2 |
| ITF - M25 Frankfurt am Main | 2021/08/09 11:55 | Max Wiskandt v Niklas Schell | 6-3,3-6,5-10 |
| ITF - M25 Marburg | 2021/07/07 13:00 | Louis Wessels v Niklas Schell | 6-3,6-4 |
| ITF M25 - Klosters | 2021/06/20 08:55 | Ilias Zimmermann v Niklas Schell | 6-4,4-6,12-10 |
| ITF - M15 Antalya | 2021/05/23 07:00 | Niklas Schell v Stefano D'Agostino | 4-6,6-3,7-10 |
| ITF - M15 Troisdorf | 2021/05/09 08:00 | Marlon Vankan v Niklas Schell | 2-6,7-6,13-11 |