Colorado Rapids 1-2 Chicago Fire *
| 05.10.1998 | Chicago Fire | 1-0 | Colorado Rapids | |
| 01.10.1998 | Colorado Rapids | 1-1/p.3-2 | Chicago Fire | |
Dallas Burn 3-9 Los Angeles Galaxy *
| 04.10.1998 | Los Angeles Galaxy | 3-2 | Dallas Burn | |
| 01.10.1998 | Dallas Burn | 1-6 | Los Angeles Galaxy | |
Miami Fusion 1-2 DC United *
| 04.10.1998 | DC United | 0-0/p.3-2 | Miami Fusion | |
| 30.09.1998 | Miami Fusion | 1-2 | DC United | |
NY/NJ MetroStars 4-6 Columbus Crew *
| 03.10.1998 | Columbus Crew | 1-1/p.3-2 | NY/NJ MetroStars | |
| 30.09.1998 | NY/NJ MetroStars | 3-5 | Columbus Crew | |