SEATTLE, Wash. -- The Portland Timbers have had some rough trips to CenturyLink Field over the years.

The Timbers didn't post their first regular season win over the Sounders at CenturyLink Field until this year. Portland holds a 1-7-3 all-time MLS regular season record at CenturyLink Field as well.

But when it comes to the playoffs, the Timbers reign supreme.

The Timbers first faced their archrivals in the playoffs back in 2013 when the two clubs were pitted against each other in the Western Conference semifinal series. Portland shocked Seattle in the series, traveling to CenturyLink to earn a 2-1 win in the first leg before posting a convincing 3-2 victory over the Sounders in the second leg at Providence Park.

And Portland once again ousted their rivals from the playoffs Thursday night.

The Timbers beat the Sounders 4-2 on penalty kicks in an epic second leg of the Western Conference semifinal playoff series Thursday at CenturyLink Field.

"We know playing against Seattle is very important for the fans and for us too," Timbers midfielder Diego Chara said. "It's the moment of the season in the semifinals. To beat Seattle is an amazing feeling."

The Timbers entered Thursday's game with a 2-1 lead in the series after winning at home in the first leg, but fell 2-1 to the Sounders in a tense regulation match at CenturyLink Field. With the series tied 3-3 on aggregate, the clubs headed to extra time where the two teams swapped goals over the next half hour before going to penalties. Timbers forward Dairon Asprilla scored the game-winning penalty kick to start the celebration for the Timbers. It might have been one of the most memorable playoff matches in MLS history.

"Games versus Seattle are big for the city," Timbers goalkeeper Jeff Attinella said. "It's big for the fans. It's big for everybody. I'm glad that we were able to do it. I'm glad that we were able to do it here."

Along with their dominance over the Sounders in the postseason, the Timbers also ousted their other Cascadia rival, the Vancouver Whitecaps, in the 2013 Western Conference semifinal round of the MLS Cup Playoffs, posting a 2-0 win over Vancouver at BC Place in the second leg of the series.

Portland went on to win the 2015 MLS Cup, becoming the first Cascadia team to claim the title.

Those are some bragging rights.

-- Jamie Goldberg | jgoldberg@oregonian.com

503-853-3761 | @jamiebgoldberg