| 1. Round | 14/03/1998 | Miami Fusion | - | D.C. United | 0:2 | ||||
| 1. Round | 20/03/1998 | D.C. United | - | Kansas City Wizards | 3:2 | ||||
| 1. Round | 28/03/1998 | D.C. United | - | New England Revolution | n.P. | ||||
| 2. Round | 10/04/1998 | D.C. United | - | Colorado Rapids | n.P. | ||||
| 2. Round | 17/04/1998 | New England Revolution | - | D.C. United | n.P. | ||||
| 2. Round | 25/04/1998 | D.C. United | - | Columbus Crew | n.P. | ||||
| 2. Round | 28/04/1998 | D.C. United | - | San Jose Clash | 3:1 | ||||
| 3. Round | 01/05/1998 | Chicago Fire | - | D.C. United | 1:3 |  |
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| 3. Round | 08/05/1998 | D.C. United | - | MetroStars | 2:0 | ||||
| 3. Round | 12/05/1998 | D.C. United | - | New England Revolution | 3:2 | ||||
| 3. Round | 15/05/1998 | MetroStars | - | D.C. United | 4:3 | ||||
| 4. Round | 02/06/1998 | San Jose Clash | - | D.C. United | 0:4 | ||||
| 4. Round | 06/06/1998 | D.C. United | - | Dallas Burn | n.P. | ||||
| 4. Round | 12/06/1998 | Columbus Crew | - | D.C. United | n.P. | |
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| 6. Round | 21/08/1998 | D.C. United | - | MetroStars | 2:1 | ||||
| 6. Round | 25/08/1998 | Kansas City Wizards | - | D.C. United | 1:2 | ||||
| 6. Round | 28/08/1998 | Tampa Bay Mutiny | - | D.C. United | n.P. | ||||
| 7. Round | 26/09/1998 | D.C. United | - | Columbus Crew | n.P. | |
Colombia