The Timbers were stunned by twice getting hit with a PK, and some questioned the second one.
"After one, you figure the second one has to be 100 percent sure," Jewsbury said, adding that he hadn't been able to review the video.
Said Portland defender Jorge Villafana: "There's always calls. We can't do anything about them. That's the ref's position. We have to just play."
The Whitecaps scored again in the first-half-stoppage time when Hurtado, who grew up in nearby Beaverton, rebounded his own shot off Ricketts to give Vancouver a 3-1 lead.
Hurtado, who played for the Timbers' U-23s from 2011-12, has three goals in three straight matches.
Vancouver made it 4-1 with Jordan Harvey's goal from the top of the box just 9 minutes into the second half. But Portland closed the gap in the 77th minute with Gaston Fernandez's well-placed header off a cross from Diego Valeri. It was Fernandez's sixth goal of the year.
Portland captain Will Johnson narrowed it further with a goal in the 85th minute and as Robinson said, "suddenly I'm sweating." But the rally came up short.
Going into the match, the Timbers were 4-0-4 against the Whitecaps since the teams joined Major League Soccer in 2011.
The Sounders and Timbers played to a 4-4 draw in early April to kick off the regional competition. Vancouver and Seattle played to another draw last weekend at BC Place.
Before their win Sunday, the Whitecaps were the only Western Conference team that hadn't beaten the Timbers.