| 1. Round | 25/03/2018 | Colorado Springs Switchbacks | - | Portland Timbers 2 | 0:1 |  |
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| 1. Round | 31/03/2018 | Real Monarchs SLC | - | Portland Timbers 2 | 4:2 |  |
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| 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 | |
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| 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 | |
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| 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 | ||||
| 3. Round | 13/05/2018 | Seattle Sounders 2 | - | Portland Timbers 2 | 0:1 | ||||
| 3. Round | 18/05/2018 | Portland Timbers 2 | - | Los Angeles Galaxy II | 7:3 | |
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| 7. Round | 02/09/2018 | Portland Timbers 2 | - | Saint Louis FC | 1:0 | |
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| 7. Round | 09/09/2018 | Portland Timbers 2 | - | Tulsa Roughnecks | 4:0 | |
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| 7. Round | 17/09/2018 | Las Vegas Lights FC | - | Portland Timbers 2 | 1:2 | |
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| 7. Round | 23/09/2018 | Fresno FC | - | Portland Timbers 2 | 2:2 | ||||
| 7. Round | 30/09/2018 | Sacramento Republic | - | Portland Timbers 2 | 1:0 |
Colombia