Thanks to a 2-1 win over the San Jose Earthquakes and a Colorado Rapids win over FC Dallas, the Seattle Sounders secured the No. 2 seed and a bye in the Audi 2018 MLS Cup Playoffs. The West finished like this:
1. Sporting Kansas City
2. Seattle Sounders
3. LAFC
4. FC Dallas
5. Portland Timbers
6. Real Salt Lake
No. 3 LAFC will host No. 6 RSL, and No. 4 FC Dallas will host No. 5 Portland. MLS reseeds, so the Sounders will play the higher remaining seed, while Sporting KC will play the lower seed.
The Sounders will play LAFC IF:
- LAFC defeats RSL
The Sounders will play FC Dallas IF:
- FC Dallas defeats Portland AND
- RSL defeats LAFC
The Sounders will play Portland IF:
- Portland defeats FC Dallas AND
- RSL defeats LAFC
Leg 1 of the Western Conference Semifinals will take place on the road on Sunday, November 4 with Leg 2 taking place at CenturyLink Field on Thursday, November 8. Kickoff times are to be determined.