League-leading FCD came back from two goals down to briefly equalize, before Seattle regained its two-goal cushion.
The opening goal came from a Dallas goal kick. Osvaldo Alonso headed it back the other direction, where Eddie Johnson burst between two defenders. The U.S. international flicked the ball past Raúl Fernández with the outside of his right boot a quarter hour into the match.
The Sounders doubled their lead after half an hour when Brad Evans sprung Dallas' high offside trap. Lamar Neagle rounded Fernaández and scored.
Dallas stunned the hosts by scoring two set piece in seven minutes. First, Kenny Cooper redirected a long Michel free kick with a glancing header to claw one back. Then Michel himself scored after the hour mark, notching an olimpico straight from a corner.
Parity lasted one minute. DeAndre Yedlin stole back the ball and fed Shalrie Joseph, who passed to Neagle. After holding off his marker, Neagle thread the ball through the defense. Johnson feigned to slip past Fernández and coolly finished.
With a quarter hour remaining, a high Blas Perez elbow caught Leo Gonzalez. Blood poured from the fullback's nose. Perez's card matched the red on Gonzalez's face.
Substitute Obafemi Martins finished off the scoring off another Evans assist.