Stadium: Court 1 Round: 25 Ground: Clay
| ITF M15 Troisdorf | 2021/05/13 09:00 | Kai Wehnelt v Lucas Gerch | 4-6,6-4,5-7 |
| ITF M25 Alkmaar | 2021/06/24 08:00 | Mats Rosenkranz v Kai Wehnelt | 6-1,4-6,5-7 |
| ITF M25 Alkmaar | 2021/06/23 16:10 | Kai Wehnelt v Sander Jong | 6-2,7-6 |
| ITF M25 Alkmaar | 2021/06/21 16:00 | Kai Wehnelt v Deney Wassermann | 5-7,6-3,12-10 |
| ITF M15 Bucharest | 2021/05/26 08:30 | Kai Wehnelt v Cristian Rodriguez | 6-7,3-6 |
| ITF M15 Troisdorf | 2021/05/13 09:00 | Kai Wehnelt v Lucas Gerch | 4-6,6-4,5-7 |
| ITF M15 Troisdorf | 2021/05/11 12:35 | Tomas Lipovsek Puches v Kai Wehnelt | 1-6,7-6,3-6 |
| ITF M15 Cairo | 2021/05/06 07:50 | Jose Fco. Vidal Azorin v Kai Wehnelt | 6-4,6-3 |
| ITF M15 Cairo | 2021/05/05 09:45 | Hanwen Li v Kai Wehnelt | 3-6,4-6 |
| ITF M25 The Hague | 2021/07/01 09:55 | Manuel Guinard v Lucas Gerch | 6-3,6-2 |
| ITF M25 The Hague | 2021/06/29 11:20 | Lucas Gerch v Vladimir Ivanov | 6-1,6-2 |
| Challenger Forli | 2021/06/16 09:30 | Francesco Forti v Lucas Gerch | 6-4,6-4 |
| Challenger Forli | 2021/06/15 09:30 | Lucas Gerch v Thiago Agustin Tirante | 7-6,3-6,6-3 |
| Challenger Forli | 2021/06/14 09:30 | Lucas Gerch v Elmar Ejupovic | 4-6,6-4,7-6 |
| Challenger Forli | 2021/06/13 09:45 | Alessandro Bega v Lucas Gerch | 3-6,1-6 |
| ITF M15 Antalya | 2021/05/28 08:20 | Pol Martin Tiffon v Lucas Gerch | 7-5,6-3 |
| ITF M15 Antalya | 2021/05/27 10:10 | Paul Woerner v Lucas Gerch | 7-5,6-7,3-6 |