| India PBL | 02/08 14:30 | - | Sai Praneeth, B. v Sakai, Kazumasa | W | 0-2 | |
| India PBL | 02/03 14:50 | - | Jayaram, Ajay v Sakai, Kazumasa | L | 2-1 | |
| India PBL | 02/01 10:00 | - | Sakai, Kazumasa v Saensomboonsuk, Tanongsak | L | 0-2 | |
| India PBL | 01/30 11:20 | - | Sakai, Kazumasa v S.K. Karunakaran | W | 2-0 | |
| India PBL | 01/27 13:50 | - | Sakai, Kazumasa v Yadav, Ansal | W | 2-0 | |
| India PBL | 01/25 14:30 | - | Sakai, Kazumasa v Lee, Dong Keun | L | 0-2 | |
| Korea Masters | 11/20 00:40 | 5 | Sakai, Kazumasa v Sameer Verma | - | Retired | |
| Indonesia Masters | 10/02 12:20 | 5 | Sakai, Kazumasa v Prasetyo, Wisnu Yuli | L | 0-2 | |
| Chinese Taipei Open 2019, MS | 09/04 10:40 | 5 | Sakai, Kazumasa v Verma, Sourabh | L | 0-2 | |
| Akita Masters 2019, MS | 08/15 02:15 | 4 | Sakai, Kazumasa v Igarashi, Yu | L | 1-2 | |
| Akita Masters 2019, MS | 08/14 03:30 | 5 | Sakai, Kazumasa v Kodai Naraoka | W | 2-0 | |
| US Open 2019, MS | 07/11 21:15 | 4 | Saensomboonsuk, Tanongsak v Sakai, Kazumasa | L | 2-0 | |
| US Open 2019, MS | 07/10 21:15 | 5 | Lam, Timothy v Sakai, Kazumasa | W | 0-2 | |
| Canada Open | 07/03 17:50 | 5 | Sakai, Kazumasa v Heo, Kwang Hee | L | 0-2 | |
| Australian Open | 06/07 08:00 | 3 | Tzu Wei Wang v Sakai, Kazumasa | L | 2-0 | |
| Australian Open | 06/06 03:45 | 4 | Sakai, Kazumasa v Kantaphon Wangcharoen | W | 2-1 | |
| Australian Open | 06/05 01:40 | 5 | Sakai, Kazumasa v Cheuk Yiu Lee | W | 2-0 | |
| New Zealand Open 2019, MS | 05/02 02:40 | 4 | Zii Jia Lee v Sakai, Kazumasa | L | 2-0 | |
| New Zealand Open 2019, MS | 05/01 02:00 | 5 | Zhou, Z. Q. v Sakai, Kazumasa | W | 1-2 | |
| Asia Championships | 04/24 04:00 | 5 | Sameer Verma v Sakai, Kazumasa | L | 2-1 | |
| Osaka Int. | 04/04 00:00 | - | Sakai, Kazumasa v Kim, Donghun (1993) | D | Retired | |
| Open d'Angleterre | 03/06 16:00 | 5 | Joergensen, J. O. v Sakai, Kazumasa | L | 2-0 | |
| German Open | 02/27 18:45 | 5 | Cheuk Yiu Lee v Sakai, Kazumasa | L | 2-0 | |
| Indonesia Masters | 01/23 02:30 | 5 | Thammasin, S. v Sakai, Kazumasa | L | 2-0 | |
| Indonesia Masters XD | 01/16 11:05 | 5 | Viktor Axelsen v Sakai, Kazumasa | L | 2-0 | |
| Indonesia Masters XD | 11/14 12:45 | 5 | Jonatan Christie v Sakai, Kazumasa | L | 2-0 | |
| Open d'Angleterre | 11/08 04:50 | 4 | Sakai, Kazumasa v Shi, Y. Q. | L | 0-2 | |
| Open d'Angleterre | 11/07 06:15 | 5 | Avihingsanon, Suppanyu v Sakai, Kazumasa | W | 1-2 | |
| Open de France | 10/25 12:40 | 4 | Kento Momota v Sakai, Kazumasa | L | 2-0 | |
| Open de France | 10/24 11:00 | 5 | Sakai, Kazumasa v Lin, Dan | W | 2-1 |