In what proved to an eventful first half in which both sides had chances, it was the hosts who drew first blood after breaking the deadlock in the 41st minute.
Darlington Nagbe found the target from the centre of the Vancouver penalty box with a right-footed shot after being released by Jack Jewsbury.
However, Portland's lead lasted for just five minutes as in the second minute of injury time Kenny Miller equalised from close range.
Ten minutes into the second half Portland regained their one-goal advantage when Franck Songo'o scored from a free kick.
The hosts continued to create chances as the second half progressed, with Bright Dike coming close to scoring in the 64th minute.
Vancouver failed to conjure anything productive and were reduced to 10 men in the 84th minute when Darren Mattocks was given his marching orders.
Portland saw out the remainder of this Western Conference game with ease and picked up maximum points.