Stadium: Court 3 Round: 26 Ground: Hardcourt indoor
| ITF Finland F1 | 2018/07/30 07:00 | Siimar, Mattias v Kristjan Tamm | 6-1,6-2 |
| ITF M15 Parnu | 2020/11/04 08:00 | Siimar, Mattias v Hietaranta, Roni Mikael | 6-3,6-2 |
| ITF M15 East Lansing | 2019/11/20 21:15 | Cannon Kingsley v Siimar, Mattias | 7-5,6-2 |
| ITF M15 Helsinki | 2019/08/20 08:30 | Siimar, Mattias v Rikkonen, Roni | 5-7,6-0,9-11 |
| ITF M15 Helsinki | 2019/08/19 10:00 | Siimar, Mattias v Vanko, Tomas | 6-1,6-0 |
| ITF M15 Parnu | 2019/07/15 07:00 | Siimar, Mattias v Tadas Babelis | 6-2,3-6,13-15 |
| ITF Finland F2 | 2018/08/08 12:55 | Siimar, Mattias v Hansson, Gustav | 2-6,2-6 |
| ITF Finland F2 | 2018/08/06 08:00 | Siim Troost v Siimar, Mattias | 6-2,1-6,0-6 |
| ITF Finland F1 | 2018/08/02 11:00 | Siimar, Mattias v Niklas-Salminen, Patrick | 4-6,6-7 |
| ITF M15 Parnu | 2020/11/04 09:25 | Kristjan Tamm v Erler, Alexander | 7-6,4-6,7-6 |
| Sarreguemines, Singles M-ITF-FRA-22A | 2020/10/25 09:00 | Kristjan Tamm v Leopold Zima | 2-6,3-6 |
| ITF - M15 Monastir | 2020/10/22 08:00 | Kristjan Tamm v Daniil Glinka | 5-7,6-7 |
| ITF - M15 Monastir | 2020/10/21 08:00 | Kristjan Tamm v Martinez, Mirko | 4-6,6-3,6-2 |
| ITF - M15 Monastir | 2020/10/15 11:05 | Thiago Agustin Tirante v Kristjan Tamm | 6-2,6-4 |
| ITF - M15 Monastir | 2020/10/13 10:55 | Sibille, Imran v Kristjan Tamm | 2-6,1-6 |
| ITF - M15 Monastir | 2020/10/07 11:50 | Bortolotti, Marco v Kristjan Tamm | 6-2,6-1 |
| ITF - M15 Monastir | 2020/09/29 08:00 | Aziz Ouakaa v Kristjan Tamm | 7-6,2-6,6-2 |