Seattle (8-3-2) was awarded the kick after defender Jay DeMerit fouled Cam Weaver in the penalty area.
Vancouver (4-2-5) took a 2-1 lead in the 66th minute when midfielder Gershon Koffie scored his first goal of the season on an error by goalkeeper Stefan Frei. In an effort to keep the ball in play, Frei ventured way out of his net and booted a clearing attempt up the middle instead of safely up the sideline. Koffie pounced on the ball and scored into the vacated goal.
Seattle's Chad Barrett opened the scoring in the 36th minute, and Erik Hurtado tied it in the 39th.
The Sounders return to action Saturday against Real Salt Lake.