| Challenger St. Petersburg | 03/08 10:00 | 25 | [311] Duje Ajdukovic v Sekiguchi, Shuichi [301] | 7-5,6-2 | |
| Challenger St. Petersburg | 03/01 13:45 | 25 | [299] Sekiguchi, Shuichi v Cem Ilkel [210] | 3-6,2-6 | |
| Istanbul, Turkey | 10/17 08:50 | 26 | Sekiguchi, Shuichi v Galovic, Viktor | Cancelled | |
| ITF M25 Rodez | 10/14 12:20 | 25 | [363] Hamou, Maxime v Sekiguchi, Shuichi [279] | 4-6,7-6,7-6 | |
| ITF M25 Porto | 10/03 09:00 | 27 | Sekiguchi, Shuichi v Gastao Elias | 2-6,3-6 | |
| ITF M25 Porto | 10/01 13:00 | 26 | [276] Sekiguchi, Shuichi v Niklas-Salminen, Patrick [431] | 3-6,6-2,6-3 | |
| ITF M25 Porto | 09/30 14:15 | 25 | [276] Sekiguchi, Shuichi v Doumbia, Sadio [380] | 6-4,7-6 | |
| Challenger Sibiu | 09/23 11:50 | 26 | [274] Sekiguchi, Shuichi v Felipe M R Alves [316] | 2-6,3-6 | |
| Challenger Sibiu | 09/22 08:00 | 25 | Sekiguchi, Shuichi v Dima, Dragos | 7-5,7-6 | |
| Nonthaburi, Singles M-ITF-THA-01A | 01/31 05:00 | 27 | [395] Matija Pecotic v Sekiguchi, Shuichi [264] | 6-2,7-5 | |
| Nonthaburi, Singles M-ITF-THA-01A | 01/30 07:05 | 26 | Na, Jung-Woong v Sekiguchi, Shuichi | 1-6,4-6 | |
| Nonthaburi, Singles M-ITF-THA-01A | 01/29 07:25 | 25 | Kasidit Samrej v Sekiguchi, Shuichi | 3-6,2-6 | |
| Bangkok-2, Thailand | 01/22 05:25 | 25 | [180] Polansky, Peter v Sekiguchi, Shuichi [264] | 6-3,7-5 | |
| Bangkok-2, Thailand | 01/21 03:00 | 24 | [249] Galovic, Viktor v Sekiguchi, Shuichi [264] | Retired | |
| ATP - Auckland | 01/10 22:00 | 64 | [260] Sekiguchi, Shuichi v Tatsuma Ito [145] | 3-6,6-4,4-6 | |
| Te Anau, Simples M-ITF-NZL-01A | 01/04 00:30 | 28 | [321] Luke Saville v Sekiguchi, Shuichi [262] | 6-3,6-3 | |
| Te Anau, Simples M-ITF-NZL-01A | 01/02 21:00 | 27 | Stoupe, George v Sekiguchi, Shuichi | 3-6,1-6 | |
| Te Anau, Simples M-ITF-NZL-01A | 01/01 22:00 | 26 | [381] Calum Puttergill v Sekiguchi, Shuichi [262] | 6-2,2-6,2-6 | |
| Te Anau, Simples M-ITF-NZL-01A | 12/31 05:15 | 25 | Sam Ryan Ziegann v Sekiguchi, Shuichi | 2-6,3-6 | |
| Challenger - Pune | 11/14 06:30 | 26 | [270] Sekiguchi, Shuichi v Ortega-Olmedo, Roberto [248] | 2-6,4-6 | |
| Challenger - Pune | 11/12 07:45 | 25 | Sekiguchi, Shuichi v Blokhin, Roman | 6-3,6-0 | |
| Challenger Kobe | 11/04 02:40 | 24 | Patael, Ben v Sekiguchi, Shuichi | 6-3,6-2 | |
| Playford City II, Australie | 10/31 02:55 | 26 | [137] Marc Polmans v Sekiguchi, Shuichi [272] | 6-3,6-4 | |
| Playford City II, Australie | 10/29 02:20 | 25 | Matthew C Romios v Sekiguchi, Shuichi | 3-6,1-6 | |
| Challenger Traralgon | 10/24 02:45 | 26 | [87] Yasutaka Uchiyama v Sekiguchi, Shuichi [278] | 6-4,3-6,7-5 | |
| Challenger Traralgon | 10/22 02:05 | 25 | [374] Kelly, Dayne v Sekiguchi, Shuichi [278] | 4-6,6-2,6-7 | |
| Ningbo, China | 10/14 08:25 | 24 | Nam, Ji Sung v Sekiguchi, Shuichi | 6-1,6-1 | |
| ITF M25 Tay Ninh | 10/11 05:00 | 27 | [446] Nguyen, Daniel v Sekiguchi, Shuichi [283] | Retired | |
| ITF M25 Tay Ninh | 10/10 03:55 | 26 | Takeuchi, Kento (1987) v Sekiguchi, Shuichi | Retired | |
| ITF M25 Tay Ninh | 10/08 05:45 | 25 | Sidharth Rawat v Sekiguchi, Shuichi | 0-6,1-6 |