Clint Dempsey broke the deadlock with a direct free kick in the 86th minute in Seattle's 2-1 comeback victory over FC Dallas in the first leg of their Western Conference semifinal.
Dempsey drove a shot from 25 yards into the upper right side of the net. He also scored on Wednesday night in the Sounders' 3-2 knockout-round victory over the LA Galaxy.
Andreas Ivanschitz tied it for fourth-seeded Sounders with an unassisted goal in the 67th minute. Fabian Castillo had opened the scoring for top-seeded Dallas in the 18th minute.
The second leg of the series is next Sunday in Frisco, Texas. The Sounders will advance to the West final with a win or a tie.