Stadion: Court 3 Round: 25 Ground: Hardcourt indoor
| ITF - M15 - Parnu | 2020/11/06 08:00 | Simon Freund v Mattias Siimar | 1-6,6-3,1-6 |
| ITF - M15 - Parnu | 2020/11/05 11:10 | Mattias Siimar v Kristjan Tamm | 6-3,6-7,6-3 |
| ITF - M15 - Parnu | 2020/11/04 08:00 | Mattias Siimar v Roni Mikael Hietaranta | 6-3,6-2 |
| ITF - M15 - East Lansing | 2019/11/20 21:15 | Cannon Kingsley v Mattias Siimar | 7-5,6-2 |
| ITF - M15 - Helsinki | 2019/08/20 08:30 | Mattias Siimar v Roni Rikkonen | 5-7,6-0,9-11 |
| ITF - M15 - Helsinki | 2019/08/19 10:00 | Mattias Siimar v Tomas Vanko | 6-1,6-0 |
| ITF - M15 - Parnu | 2019/07/15 07:00 | Mattias Siimar v Tadas Babelis | 6-2,3-6,13-15 |
| ITF - Finnland F2 | 2018/08/08 12:55 | Mattias Siimar v Gustav Gustav Hansson | 2-6,2-6 |
| ITF - M15 - Castelo Branco | 2021/07/27 08:30 | Vilius Gaubas v Gilbert S K Junior | 4-6,3-6 |