| Hellas Int. Qual | 2019/05/02 12:30 | Nicolas A. Mueller v Sonderskov, Mattias | L | 2-0 |
| Croatian Int. Qual | 2019/04/18 09:20 | Sonderskov, Mattias v Borko Petrovic | L | 1-2 |
| Dutch Int. - Qualif. | 2019/04/11 07:05 | Bronselaer, Robby v Sonderskov, Mattias | W | 0-2 |
| Open de Suisse - Doubles Femmes - Qualif. | 2019/02/27 07:00 | Pearce, Luke v Sonderskov, Mattias | L | 2-0 |
| Open de Suisse - Doubles Femmes - Qualif. | 2018/11/28 11:30 | Heinemann, Andrew v Sonderskov, Mattias | L | 2-1 |
| Open de Suisse - Doubles Femmes - Qualif. | 2018/04/12 10:35 | Sonderskov, Mattias v Aram Mahmoud | L | 0-2 |
| Indonesia Masters XD | 2017/10/31 17:00 | Sonderskov, Mattias v Offermann, Christoph | L | 0-2 |
| Open de Suisse - Doubles Femmes - Qualif. | 2017/10/31 10:00 | Purusothaman, Thiyagarajan v Sonderskov, Mattias | W | 0-2 |
| Denmark Int. Qual | 2019/05/09 12:20 | Julien Carraggi v Magnus Johannesen | L | 2-1 |