Stadium: Court 8 Round: 25 Ground: Hardcourt outdoor
| ITF M15 Kofu | 2019/03/19 01:00 | Keisuke Saitoh v Jumpei Yamasaki | 2-6,3-6 |
| ITF M15 Monastir | 2021/08/24 07:30 | Keisuke Saitoh v Rishi Reddy | 6-4,6-3 |
| ITF M15 Monastir | 2021/08/23 08:00 | Keisuke Saitoh v Bastian A U Santander | 6-2,6-0 |
| ITF M15 Monastir | 2021/08/22 07:30 | Keisuke Saitoh v Bryan Aguiar Kuntz | 6-4,6-4 |
| ITF M15 Monastir | 2021/08/16 08:30 | Keisuke Saitoh v Shohei Chikami | 4-6,1-6 |
| ITF M15 Monastir | 2021/08/15 11:00 | Keisuke Saitoh v Alec Beckley | 6-3,4-6,10-4 |
| ITF M15 Monastir | 2021/08/11 18:35 | Keisuke Saitoh v Dane Sweeny | 1-6,4-6 |
| ITF M15 Monastir | 2021/08/10 07:30 | Masamichi Imamura v Keisuke Saitoh | 6-7,2-6 |
| ITF M15 Monastir | 2021/08/09 07:30 | Babji Siva Atturu v Keisuke Saitoh | 1-6,0-6 |
| ITF M15 Monastir | 2021/08/18 07:30 | Mateo Nicolas Martinez v Jumpei Yamasaki | 5-7,6-1,7-5 |
| ITF M15 Monastir | 2021/08/11 18:25 | Sho Shimabukuro v Jumpei Yamasaki | 6-3,6-2 |
| ITF M25 Decatur | 2021/08/05 17:55 | Jumpei Yamasaki v Yunseong Chung | 2-6,2-6 |
| ITF M25 Decatur | 2021/08/04 21:50 | Aleksandar Kovacevic v Jumpei Yamasaki | 4-6,6-3,3-6 |
| ITF M25 Decatur | 2021/08/03 17:10 | Jumpei Yamasaki v Stefan Dostanic | 6-4,6-4 |
| ITF M25 Decatur | 2021/08/02 15:00 | Jumpei Yamasaki v Carson Haskins | 6-1,6-2 |
| ITF M25 Champaign | 2021/07/29 17:00 | Gijs Brouwer v Jumpei Yamasaki | 6-3,6-0 |
| ITF M25 Champaign | 2021/07/28 19:10 | Martin Damm v Jumpei Yamasaki | 6-7,6-7 |