Valeri scores twice in 2-1 win to give Timbers knockout win
Valeri's first goal came in the 23rd minute on a free kick that he put inside the left post from 26 yards out.
But in the 71st, Jeremy Ebobisse dropped off a short pass to Valeri in the goal box amid a scattered Dallas defense and Valeri nudged the ball into the net for his team-leading 12th goal.
Dallas broke through in the 94th minute with Matt Hedges heading in a goal but couldn't come up with another despite a few additional chances in stoppage time.
Timbers keeper Jeff Attinella made five saves.
Portland came in with just four road wins this season, while fourth-seeded Dallas had been 10-2-5 at home. But Dallas also entered the postseason on a three-game losing streak, scoring just one goal in that span.