Paul Rothrock scored and set up Albert Rusnak to give Seattle a 1-0 lead, though Hassani Dotson's debut goal was waved off for a foul. Noah Cobb's red card was downgraded to a yellow. Rothrock added an insurance goal late, while Andrew Thomas made four saves for the clean sheet.
Zack Steffen saved three shots for Colorado. The Sounders won't play another home match until April 12 due to stadium updates. Up next for Seattle is a trip to Real Salt Lake on Saturday.