| 1. Round | 25/03/2018 | Colorado Springs Switchbacks | - | Portland Timbers 2 | 0:1 | ||||
| 2. Round | 05/04/2018 | Tulsa Roughnecks | - | Portland Timbers 2 | 0:0 |  |
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| 2. Round | 08/04/2018 | OKC Energy FC | - | Portland Timbers 2 | 0:3 | ||||
| 2. Round | 19/04/2018 | Portland Timbers 2 | - | Rio Grande Valley FC | 3:2 | ||||
| 2. Round | 22/04/2018 | Portland Timbers 2 | - | Reno 1868 FC | 1:2 | ||||
| 3. Round | 03/05/2018 | Portland Timbers 2 | - | Sacramento Republic | 2:0 | ||||
| 3. Round | 06/05/2018 | Saint Louis FC | - | Portland Timbers 2 | 0:0 | |
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| 3. Round | 13/05/2018 | Seattle Sounders 2 | - | Portland Timbers 2 | 0:1 |  |
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| 3. Round | 18/05/2018 | Portland Timbers 2 | - | Los Angeles Galaxy II | 7:3 | |
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| 3. Round | 26/05/2018 | Portland Timbers 2 | - | Real Monarchs SLC | 1:0 | ||||
| 5. Round | 08/07/2018 | Portland Timbers 2 | - | Fresno FC | 2:4 | ||||
| 5. Round | 15/07/2018 | Portland Timbers 2 | - | Swope Park Rangers | 2:1 | |
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| 5. Round | 22/07/2018 | Portland Timbers 2 | - | Las Vegas Lights FC | 1:2 | ||||
| 5. Round | 28/07/2018 | Los Angeles Galaxy II | - | Portland Timbers 2 | 3:4 | |
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| 6. Round | 16/08/2018 | Portland Timbers 2 | - | San Antonio FC | 2:1 |
USA