Portland (16-13-4, 52 points) beat RSL for a third time this season, clinching a top-four spot in the West and a home game in the MLS Cup playoffs. The Timbers' potent offense overwhelmed Salt Lake once again, as Portland scored 12 goals against RSL this year.
Salt Lake (13-14-6, 45 points) would have clinched a playoff berth with a victory but is now facing long odds of qualifying after losing its second straight home match. Real Salt Lake sit in eighth place in the West, two points back of the Los Angeles Galaxy, who hold the seventh and final playoff position.
RSL, who lost for the fourth time in six matches, will need help to reach the postseason even with a win in the regular-season finale at Sporting Kansas City on Sunday.
Portland struck first in the 17th minute, scoring on a header from Blanco that came against the run of play. Cristhian Paredes sent a header into the 6-yard box off of a corner kick. Blanco got to the ball after Maikael Chang got caught flat-footed at the near post and redirected it into the back post.
RSL's porous backline ultimately dug a huge hole for the Utah club before halftime.
A defensive mistake extended the Timbers' lead to 2-0 in the 38th minute. Aaron Herrera was credited with an own goal after Blanco fired the ball into the 6-yard box while being challenged by Glad.
Blanco capped off a takeaway with his second goal in the 45th minute. He dribbled down, laid the ball off to Jaroslaw Niezgoda and blasted a shot down the middle when Niezgoda sent a pass back to him.
Rusnak pulled a goal back for RSL after bouncing a penalty kick off the crossbar and into the net in the 88th minute.