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