Mabiala headed home Diego Valeri's free kick to open the scoring for the Timbers (1-5-1) in the 31st minute. Crew goalkeeper Zack Steffen got his hands on the shot but not enough to deny the goal.
Ebobisse doubled Portland's lead four minutes later, finding an open space at the top of the 6-yard box to finish Sebastián Blanco's cross.
Jorge Moreira capped the scoring in second-half stoppage time with a right-footed shot from close range for the Timbers.
Pedro Santos pulled the Crew (4-3-1) to 2-1 in the 69th minute with a chip shot to capitalize on a failed clearance attempt by goalkeeper Jeff Attinella.
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