Felipe Mora also scored off a Blanco assist for Portland (10-10-4, 34 points), which rallied from 1-0 and 2-1 deficits in the second half while being down a man from the 42nd minute on after Bill Tuiloma received his second yellow card for hard fouls.
Blanco's goal in the first of six minutes of extra time came after Dairon Asprilla drove the ball to the end line on the left wing. His cross bounced off a defender and to Blanco just outside of the top of the 6-yard box. Blanco's left-footed shot went straight down the middle and into the back of the net, extending Portland's unbeaten streak to four matches (3-0-1).
The Rapids had regained the lead just four minutes earlier. Barrios came off the bench and scored his team-leading seventh goal of the season from an awkward angle near the end line on the right wing, the ball going just over Portland goalkeeper Steve Clark and into the far side netting.
Lewis opened the scoring in the 64th minute, off assists from Andre Shinyashiki and Mark-Anthony Kaye. The Rapids moved the ball down the middle of the field and Kaye passed to Shinyashiki on the right wing inside the 18-yard box. Shinyashiki had to make a sliding attempt to reach the pass and he pulled it back to Lewis, whose one-timer from 10 yards out made its way just inside the right post.
The Timbers wasted little time in getting the equalizer. A free kick by Blanco from about 30 yards out on the right wing toward the far post went off the leg of Portland's Dario Zuparic and bounced across the goalmouth to Mora, who put a diving header into the open side of the net.