| 1. Round | 25/03/2018 | Swope Park Rangers | - | Seattle Sounders 2 | 4:2 | ||||
| 5. Round | 02/07/2018 | Los Angeles Galaxy II | - | Seattle Sounders 2 | 5:3 | ||||
| 5. Round | 06/07/2018 | Seattle Sounders 2 | - | Swope Park Rangers | 0:2 | ||||
| 5. Round | 08/07/2018 | Seattle Sounders 2 | - | Reno 1868 FC | 1:2 |
USA