Now they're eyeing the conference finals.
The Timbers finished the regular season ranked atop the conference standings and hold a 2-1 advantage going into Thursday's second leg of their two-game goal-aggregate conference semifinal against the rival Seattle Sounders.
The Timbers get the second leg at home - a place where they've been tremendously successful this season with an MLS-record 11 shutouts. Portland has an 11-1-5 home record and a 15-match unbeaten streak at Jeld-Wen Field. The team's lone loss came on March 9 to Montreal.
"This team is very confident right now," midfielder Jack Jewsbury said. "We're very comfortable in the way we're playing. We can morph into different teams depending how the game is going. If it's direct, we can fight with you. If it settles down, we can possess and go that way."
For the first leg on Saturday night in Seattle, Ryan Johnson flicked in a header early in the first half and Darlington Nagbe added a goal in the second for the Timbers.
Osvaldo Alonso scored in the 90th minute for the Sounders, who need to win Thursday by at least two goals to win the aggregate total and advance. Seattle will be trying to become the fourth team to accomplish the comeback since the league went to the format for its conference semifinals in 2003.
The Sounders have been to the playoffs in each of the last five seasons. The Timbers, who joined MLS in 2011, are making their first trip.
Adding to the storyline is the intense rivalry between the two clubs, which dates back to 1975 when both were part of the North American Soccer league. For nearly a decade the teams have battled with the Vancouver Whitecaps for the supporter-created Cascadia Cup.
Seattle will go into the second leg without forward Lamar Neagle due to yellow card accumulations, but are hopeful of having forward Obafemi Martins and defender DeAndre Yedlin healthy enough to contribute some minutes. Martins has been out with a groin injury while Yedlin has an ankle injury.
It was a far different situation for the Timbers last season, when they finished 8-16-10. The team dismissed fiery Scottish coach John Spencer in June and waited for new coach Caleb Porter to finish up the college season with the University of Akron.
Porter's appointment turned out to be a season changer for Portland. The measured coach is business-like in his approach to the team, instilling a strong work ethic and a patience that has kept the Timbers grounded this year.
"I think for this team to come in here and to get a result says a lot about how far we've come," Porter said after the first-leg win against Seattle. "It says a lot about this team. It says a lot about how seasoned we are even though we've not been together very long."
Another key was the addition of Diego Valeri, who led the Timbers with 10 goals and 13 assists in his first season with the team. He is the first Portland player with 10 or more goals and assists in a single season.
The Timbers finished 14-5-15 overall, a 23-point improvement in points and a 43-goal improvement in goal differential over last season for the biggest turnaround in MLS history.
The winner Thursday night will advance to the Western Conference final against the winner of the other semifinal between the two-time defending league champion Los Angeles Galaxy and Real Salt Lake.
Sean Franklin scored on a dramatic 27-yard strike just after halftime to give the Galaxy a 1-0 victory on Sunday night for the advantage.