Stadium: Court 1 Round: 28 Ground: Clay
| Challenger Seoul Qual | 2018/04/28 03:05 | Ho-Gi Kang v Takuto Niki | 6-7,6-2,0-6 |
| ITF Japan F6 | 2018/04/11 01:00 | Makoto Ochi v Takuto Niki | 7-5,6-3 |
| ITF Japan F5 | 2018/04/04 01:00 | Takuto Niki v Hiroyasu Ehara | 2-6,6-2,4-6 |
| ITF Japan F5 | 2018/04/02 05:40 | Takuto Niki v Yuta Shimizu | 6-2,6-4 |
| ITF Japan F4 | 2018/03/28 02:40 | Takuto Niki v Naoki Tajima | 5-7,6-7 |
| ITF Japan F3 | 2018/03/19 03:15 | Shinji Hazawa v Takuto Niki | 7-5,6-3 |
| ITF Japan F2 | 2018/03/13 02:00 | Kaito Uesugi v Takuto Niki | 6-0,6-3 |
| ITF Japan F1 | 2018/03/10 02:00 | Daniel Nguyen v Takuto Niki | 6-3,6-4 |
| ITF Sweden F3 Qual | 2018/05/20 09:00 | Jonas Trinker v Adam Heinonen | 7-6,6-1 |
| ITF Sweden F2 | 2018/05/16 10:15 | Lukas Ollert v Jonas Trinker | 6-1,6-4 |
| ITF Sweden F2 | 2018/05/14 11:50 | Jonas Trinker v Linus Frost | 6-2,7-6 |
| ITF Turkey F17 | 2018/05/03 07:30 | Juan Pablo Varillas v Jonas Trinker | 6-2,6-1 |
| ITF Turkey F17 | 2018/05/02 07:30 | Jonas Trinker v Gabriel Schmidt | 6-4,3-6,7-6 |
| ITF Turkey F16 | 2018/04/21 09:30 | Gorazd Srbljak v Jonas Trinker | 6-4,6-3 |
| ITF Spain F2 | 2018/01/22 09:00 | Marc Fornell-Mestres v Jonas Trinker | 7-6,6-0 |
| ITF Spain F2 | 2018/01/21 11:30 | Oscar M Cornella v Jonas Trinker | 1-6,4-6 |