| Hungarian Int. Qual | 2019/10/30 17:10 | Leon Seiwald v Tobias Kuenzi | L | 0-2 |
| Polish Int. | 2019/09/21 09:55 | Ivan Rusev v Leon Seiwald | L | 2-0 |
| Polish Int. | 2019/09/20 10:20 | Leon Seiwald v Joonas Korhonen | W | 2-1 |
| Belgian International 2019, MS | 2019/09/12 13:00 | Luis Enrique Penalver v Leon Seiwald | L | 2-1 |
| Kharkiv International 2019, MS, Qualification | 2019/09/04 11:30 | Leon Seiwald v Gergo Pytel | L | 1-2 |
| Belarus Int. | 2019/08/30 10:40 | Must, Raul v Leon Seiwald | L | 2-1 |
| Slovenia Int. Qual | 2019/05/15 08:30 | Leon Seiwald v B.M. Rahul Bharadwaj | L | 0-2 |
| Open de Suisse - Doubles Femmes - Qualif. | 2019/02/21 09:10 | Setiabudi, Bobby v Leon Seiwald | L | 2-0 |