| ITF - Korea F5 | 2018/08/18 02:00 | Jumpei Yamasaki v Dukyoung Kim | 6-4,6-4 |
| Challenger - Gwangju - Qualifikation | 2018/08/12 01:30 | Yecong He v Jumpei Yamasaki | 6-2,6-4 |
| Challenger - Gwangju - Qualifikation | 2018/08/11 01:30 | Fajing Sun v Jumpei Yamasaki | 1-6,6-2,2-6 |
| Challenger - Jinan - Qualifikation | 2018/08/04 02:00 | Matej Sabanov v Jumpei Yamasaki | 6-4,6-4 |
| Challenger - Chengdu - Qualifikation | 2018/07/28 02:00 | Miliaan Niesten v Jumpei Yamasaki | 6-2,6-2 |
| Challenger - Granby - Qualifikation | 2018/07/21 16:25 | Taha Baadi v Jumpei Yamasaki | 7-6,6-4 |
| Challenger - Gatineau - Qualifikation | 2018/07/14 21:55 | Jacob Grills v Jumpei Yamasaki | 6-3,6-1 |
| Challenger - Winnipeg - Qualifikation | 2018/07/08 18:05 | Sem Verbeek v Jumpei Yamasaki | 7-6,7-6 |
| ITF - Korea F4 | 2018/08/12 02:00 | Jungwon Park v Hyeong Don Kim | 4-6,4-6 |