| Challenger de Nottingham | 06/13 12:00 | 25 | [105] Marcel Granollers v Tatsuma Ito [158] | 3-6,5-7 | |
| Challenger de Nottingham | 06/11 17:15 | 24 | [158] Tatsuma Ito v Jason Kubler [168] | 6-4,6-4 | |
| Open de Francia | 05/20 08:00 | 44 | [158] Tatsuma Ito v Johan Tatlot [260] | 2-6,6-7 | |
| Challenger Gwangju | 05/15 02:00 | 25 | [160] Tatsuma Ito v Konstantin Kravchuk [493] | Retired | |
| Challenger de Busan | 05/10 05:00 | 27 | [213] Yasutaka Uchiyama v Tatsuma Ito [160] | 4-6,6-0,6-3 | |
| Challenger de Busan | 05/09 04:40 | 26 | [160] Tatsuma Ito v Cem Ilkel [265] | 7-5,6-7,6-4 | |
| Challenger de Busan | 05/07 05:25 | 25 | [160] Tatsuma Ito v Tung-Lin Wu [292] | 6-4,7-6 | |
| Challenger de Seúl | 05/03 03:35 | 27 | [153] Tatsuma Ito v Max Purcell [268] | 7-6,6-7,3-6 | |
| Challenger de Seúl | 05/02 02:00 | 26 | [121] Lukas Lacko v Tatsuma Ito [153] | 4-6,1-6 | |
| Challenger de Seúl | 04/30 07:20 | 25 | [269] Filip Peliwo v Tatsuma Ito [153] | 5-7,2-6 | |
| Challenger de Taipéi | 04/12 07:20 | 27 | [148] Tatsuma Ito v Sergiy Stakhovsky [124] | 6-7,7-6,4-6 | |
| Challenger de Taipéi | 04/11 07:40 | 26 | [131] Kamil Majchrzak v Tatsuma Ito [148] | 7-6,6-7,6-7 | |
| Challenger de Taipéi | 04/10 05:10 | 25 | Kuan-Yi Lee v Tatsuma Ito | 3-6,3-6 | |
| ATP Miami | 03/18 20:45 | 44 | [148] Tatsuma Ito v Daniel Evans [97] | 5-7,1-6 | |
| Challenger de Phoenix | 03/14 18:30 | 26 | [148] Tatsuma Ito v Guido Andreozzi [88] | 2-6,6-3,4-6 | |
| Challenger de Phoenix | 03/13 22:05 | 25 | [49] Matthew Ebden v Tatsuma Ito [148] | 6-3,4-6,6-7 | |
| Challenger de Phoenix | 03/12 21:10 | 24 | Nathan Ponwith v Tatsuma Ito | 4-6,4-6 | |
| ATP Indian Wells | 03/09 00:10 | 23 | [148] Tatsuma Ito v Jared Donaldson [192] | 3-6,5-7 | |
| ATP Indian Wells | 03/06 23:25 | 45 | [148] Tatsuma Ito v JC Aragone [243] | 7-6,6-3 | |
| ATP Indian Wells | 03/06 04:45 | 44 | [94] Casper Ruud v Tatsuma Ito [148] | 7-6,1-6,4-6 | |
| Challenger de Yokohama | 02/28 03:25 | 26 | [138] Tatsuma Ito v Duckhee Lee [254] | 3-6,6-4,6-7 | |
| Challenger de Yokohama | 02/27 03:00 | 25 | Tatsuma Ito v Moez Echargui | 6-0,7-5 | |
| Challenger Bangkok 1A | 02/19 07:05 | 25 | [254] JC Aragone v Tatsuma Ito [132] | Retired | |
| Challenger de Bangkok | 02/16 04:00 | 28 | [223] Dudi Sela v Tatsuma Ito [141] | Retired | |
| Challenger de Bangkok | 02/15 04:00 | 27 | [235] Soonwoo Kwon v Tatsuma Ito [141] | 3-6,6-4,1-6 | |
| Challenger de Bangkok | 02/14 03:00 | 26 | [225] Alejandro D-Fokina v Tatsuma Ito [141] | 6-1,3-6,4-6 | |
| Challenger de Bangkok | 02/13 03:00 | 25 | [231] David Perez Sanz v Tatsuma Ito [141] | 4-6,2-6 | |
| Challenger de Launceston | 01/31 01:20 | 26 | [212] Jay Clarke v Tatsuma Ito [141] | 6-2,6-7,7-5 | |
| Challenger de Launceston | 01/29 23:00 | 25 | [407] Jacob Grills v Tatsuma Ito [141] | 2-6,4-6 | |
| Open de Australia | 01/14 03:55 | 23 | [150] Tatsuma Ito v Daniel Evans [189] | 5-7,1-6,6-7 |