| Challenger St. Petersburg | 03/08 10:00 | 25 | [311] Duje Ajdukovic v Shuichi Sekiguchi [301] | 7-5,6-2 | |
| Challenger St. Petersburg | 03/01 13:45 | 25 | [299] Shuichi Sekiguchi v Cem Ilkel [210] | 3-6,2-6 | |
| Challenger Istanbul | 10/17 08:50 | 26 | Shuichi Sekiguchi v Viktor Galovic | Cancelled | |
| ITF M25 Rodez | 10/14 12:20 | 25 | [363] Maxime Hamou v Shuichi Sekiguchi [279] | 4-6,7-6,7-6 | |
| ITF M25 Porto | 10/03 09:00 | 27 | Shuichi Sekiguchi v Gastao Elias | 2-6,3-6 | |
| ITF M25 Porto | 10/01 13:00 | 26 | [276] Shuichi Sekiguchi v Patrik Niklas-Salminen [431] | 3-6,6-2,6-3 | |
| ITF M25 Porto | 09/30 14:15 | 25 | [276] Shuichi Sekiguchi v Sadio Doumbia [380] | 6-4,7-6 | |
| Challenger Sibiu | 09/23 11:50 | 26 | [274] Shuichi Sekiguchi v Felipe M R Alves [316] | 2-6,3-6 | |
| Challenger Sibiu | 09/22 08:00 | 25 | Shuichi Sekiguchi v Dragos Dima | 7-5,7-6 | |
| ITF M25 Nonthaburi | 01/31 05:00 | 27 | [395] Matija Pecotic v Shuichi Sekiguchi [264] | 6-2,7-5 | |
| ITF M25 Nonthaburi | 01/30 07:05 | 26 | Jung-Woong Na v Shuichi Sekiguchi | 1-6,4-6 | |
| ITF M25 Nonthaburi | 01/29 07:25 | 25 | Kasidit Samrej v Shuichi Sekiguchi | 3-6,2-6 | |
| Challenger Bangkok 2 | 01/22 05:25 | 25 | [180] Peter Polansky v Shuichi Sekiguchi [264] | 6-3,7-5 | |
| Challenger Bangkok 2 | 01/21 03:00 | 24 | [249] Viktor Galovic v Shuichi Sekiguchi [264] | Retired | |
| ATP Auckland | 01/10 22:00 | 64 | [260] Shuichi Sekiguchi v Tatsuma Ito [145] | 3-6,6-4,4-6 | |
| ITF M15 Te Anau | 01/04 00:30 | 28 | [321] Luke Saville v Shuichi Sekiguchi [262] | 6-3,6-3 | |
| ITF M15 Te Anau | 01/02 21:00 | 27 | George Stoupe v Shuichi Sekiguchi | 3-6,1-6 | |
| ITF M15 Te Anau | 01/01 22:00 | 26 | [381] Calum Puttergill v Shuichi Sekiguchi [262] | 6-2,2-6,2-6 | |
| ITF M15 Te Anau | 12/31 05:15 | 25 | Sam Ryan Ziegann v Shuichi Sekiguchi | 2-6,3-6 | |
| Challenger Pune | 11/14 06:30 | 26 | [270] Shuichi Sekiguchi v Roberto Ortega-Olmedo [248] | 2-6,4-6 | |
| Challenger Pune | 11/12 07:45 | 25 | Shuichi Sekiguchi v Roman Blokhin | 6-3,6-0 | |
| Challenger Kobe | 11/04 02:40 | 24 | Ben Patael v Shuichi Sekiguchi | 6-3,6-2 | |
| Challenger Playford 2 | 10/31 02:55 | 26 | [137] Marc Polmans v Shuichi Sekiguchi [272] | 6-3,6-4 | |
| Challenger Playford 2 | 10/29 02:20 | 25 | Matthew C Romios v Shuichi Sekiguchi | 3-6,1-6 | |
| Challenger Traralgon | 10/24 02:45 | 26 | [87] Yasutaka Uchiyama v Shuichi Sekiguchi [278] | 6-4,3-6,7-5 | |
| Challenger Traralgon | 10/22 02:05 | 25 | [374] Dayne Kelly v Shuichi Sekiguchi [278] | 4-6,6-2,6-7 | |
| Challenger Ningbo | 10/14 08:25 | 24 | Ji Sung Nam v Shuichi Sekiguchi | 6-1,6-1 | |
| ITF M25 Tay Ninh | 10/11 05:00 | 27 | [446] Daniel Nguyen v Shuichi Sekiguchi [283] | Retired | |
| ITF M25 Tay Ninh | 10/10 03:55 | 26 | Kento Takeuchi v Shuichi Sekiguchi | Retired | |
| ITF M25 Tay Ninh | 10/08 05:45 | 25 | Sidharth Rawat v Shuichi Sekiguchi | 0-6,1-6 |