In a meeting of the bottom two teams in the Western Conference, Colorado suffered its sixth shutout of the season. The Rapids are the only team in the conference with an average of less than one goal per game.
Dike scored from close range after taking a cross by Sal Zizzo in the 45th minute.
Portland (7-13-6) climbed out of the cellar in the West and moved past Colorado into eighth place. Colorado (8-17-2) is now a point behind Portland.