Portland went into the match on a run of 14 games unbeaten in the MLS and started brightly, dominating possession in the early stages.
The Timbers were rewarded for their bright start with the opening goal on 12 minutes, with Piquionne opening his Portland account after heading home a cross from Rodney Wallace.
Just before the break Portland extended their advantage through a volley from Will Johnson, with Wallace again the architect after providing a precise pass inside the penalty area.
Colorado pressed for a way back into the match in the second half, but Deshorn Brown spurned their best chance to grab a lifeline with 20 minutes remaining.
Portland secured the three points in the 84th minute when Ryan Johnson found the net as he latched onto Wallace's pass across the face of goal.