At the end of the 1982 North American Soccer League season, the Portland Timbers franchise was forced to fold, once team expenditures outpaced club income.

Consequently, the 1–0 Sounders victory over the Timbers on August 22, 1982 ended up being the final meeting between the two sides in the North American Soccer League.

July 21, 2001, former U.S. National Team player, Brian Ching, would score the only goal in 1–0 Sounders victory over the Timbers, as over 11,000 would be in attendance in Portland.

In Seattle, Sounders defeated the Timbers 3–1 on July 22, 2006, in a hotly contested match that accumulated eight yellow cards, and one red.

[21] A cold and rainy night on March 11, 2010, Portland defeated Seattle 1–0 in a preseason community shield charity match.

In hoping to stoke the rivalry for the future 2011 Major League Soccer season — when the Timbers would be joining the Sounders in MLS — Portland unveiled a billboard displaying a Timbers crest and the words Portland, Oregon and Soccer City USA less than a mile from Qwest Field in Seattle.

[22] The billboard was broadcast to a nationwide audience on ESPN2 during halftime of the Sounders home match versus Real Salt Lake that evening.

[23] In March 2011, the Timbers defeated the Sounders 2–0 in the preseason Cascadia Summit, a round robin game event involving the two teams and their Canadian rival, Vancouver Whitecaps FC.

On October 7, 2012, Seattle hosted Portland at CenturyLink Field in front of 66,452 people, the second-largest stand-alone crowd in MLS history.

[24] In the fourth round of the 2015 U.S. Open Cup, the Sounders hosted the Timbers at the Starfire Sports Complex in Tukwila, Washington.

Seattle, the defending champions of the Open Cup, lost 3–1 and ended the match with only six players after three were sent off by the referee with red cards and Obafemi Martins was injured after all three substitutions had been used.

The final red card was given to Clint Dempsey for tearing up the notebook of referee Daniel Radford, for which he was suspended an additional three Open Cup matches.

[29] An August 2021 match at Providence Park ended in a 6–2 Sounders victory, the largest margin in the rivalry's history and the most goals conceded by the Timbers in any league competition.

[31] On August 29, 2021, the Sounders and OL Reign hosted a men's–women's doubleheader with their respective opponents from Portland (the Timbers and Thorns).

[12][34] With the close proximity of the two cities, traveling fans of both sides witness hostile environments while visiting the opposing stadium.

While many players transferred to the other rival city from when the Timbers resumed play in 2001, the most memorable was the signing of Portland's all time assist leader, and fan favorite Hugo Alcaraz-Cuellar[42] to Seattle in 2007.

That same season, Seattle star Andrew Gregor signed with Portland, thus creating tensions on the field, as the players became familiar with each other.

Former Sounders head coach Sigi Schmid said in 2010 that Seattle, Portland, and Vancouver playing in the same league again will be "something that's going to be one of the key features of MLS".

[43] Between 2004 and 2008, the USL Seattle Sounders, Portland Timbers, and Vancouver Whitecaps competed for the supporter created Cascadia Cup, to be awarded to the club who finished with the best record in each season series between the three teams.

"[44] The MLS versions of the Whitecaps, Sounders and Timbers resumed contesting the Cascadia Cup, beginning with the 2011 season.