Portland Timbers remain firmly rooted to the bottom of the Western Conference following a third consecutive MLS defeat.
Miller Bolanos struck the only goal of the game at The Home Depot Center as Club Deportivo Chivas USA moved four points above their opponents with one game in hand.
The Ecuador youth international ended a superb solo run with a fierce right-footed shot from six yards that flew into the top left corner on 16 minutes.
Portland created enough chances to take something from their visit to California, however they were incredibly wasteful with their finishing.
Kalif Alhassan failed to hit the target twice from promising positions, while Kris Boyd also spurned a glorious late chance.
