Eddie Johnson and Fredy Montero were on the scoresheet as the Sounders cruised by their arch-rivals.
Seattle opened the scoring in the 25th minute, when Adam Johansson's cross from the right flank was turned home by Futty Danso for an own goal.
The Sounders doubled their advantage just minutes later. Brad Evans found Eddie Johnson unmarked in the box, and the striker finished across his body with a first-time half volley, displaying excellent skill and precision.
The win was sealed with 30 minutes to play, after Eddie Johnson headed a throw-in towards Fredy Montero in front of the goal. Donovan Ricketts saved his initial attempt, but the Colombian and Jack Jewsbury simultaneously bundled the rebound home, with the scorekeeper awarding the goal to Montero.
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