Danso's late goal helped the Timbers (11-14-9) finish the season on a positive note after barely missing out on a playoff berth.
Alvaro Saborio scored in the 45th minute for Salt Lake (15-11-8), which had clinched a playoff berth for the fourth consecutive season a month ago and could have wrapped up third place in the Western Conference with a win.
Saborio got his 11th goal in MLS play this season when he beat Portland goalkeeper Troy Perkins as he charged toward him and chipped the ball over Perkins' head. The ball took a high bounce and bounded into the net to give Salt Lake the lead moments before halftime.
The goal from Saborio snapped a 270-minute scoreless streak for Salt Lake, going back to a 2-1 loss to Los Angeles on Oct. 1.
Portland had a chance to tie the score in the 56th minute when Jack Jewsbury lined up for a penalty kick following a handball infraction by Salt Lake. However, Jewsbury hit the ball off the crossbar.
Danso made up for the miss when he slipped behind the Salt Lake defense and scored.