The Portland Timbers and Seattle Sounders have been playing soccer against each other for so long now that it's possible to break up the history of the rivalry into several distinct eras. Sunday's match at Providence Park (4 p.m. ET, ESPN) is significant as it will be the 100th meeting between these teams.
Portland and Seattle have faced off in the North American Soccer League, the USL First Division, the A-League and in something called the Western Alliance Challenge Series. The Sounders joined Major League Soccer in 2009, the Timbers in 2011, and this modern era has been colored by the clash of personalities between two men no longer coaching either side.
Sigi Schmid and Caleb Porter used this series as a proxy for their own personal rivalry -- and it went beyond match days. After Schmid took a jab at Porter during his induction into the American Soccer Hall of Fame, Porter responded that he actually took it as a compliment, "because he's talking about me in his Hall of Fame speech."
Their constant back and forth gave the rivalry extra spice. Although Schmid has long since departed the scene, having been fired by the Sounders in July 2016 and now coaching the LA Galaxy, his influence lives on through his longtime assistant Brian Schmetzer, who took over from him. Sunday's match is also notable as the first since 2013 without Porter roaming the Timbers sideline.
And although this rivalry has always transcended the influence of just a handful of key protagonists -- the passion of the fans has always been its driving force and will again fill Providence Park with a cacophony of sound -- it is worth asking what defines the Timbers-Sounders dynamic in the year 2018.
Both of these teams feel in flux.
Under first-year coach Giovanni Savarese and playing their first five matches on the road while their stadium underwent renovations, Portland stumbled out of the gate. The Timbers have won three straight since returning home in mid-April and seem to have some positive momentum, but they still feel like a team searching for its identity under new leadership.
The Sounders enter the weekend having scored fewer goals than any other team in the Western Conference. Having stood pat at the transfer deadline despite losing forward Jordan Morris to injury for the season, and with a lack of attacking depth, the front office has endured questions about its financial commitment.
General manager Garth Lagerwey kicked off a week-long inquisition about Seattle's standing when he admitted prior to its 1-0 loss at LAFC that the team can no longer be the biggest spender in the league. Major League Soccer has changed since the Sounders joined up. Their ownership group's pockets are not as deep as the ones in Atlanta and at LAFC.
(Of note, and at odds with the long-established big brother/little brother dynamic, Portland actually ranked higher in team payroll than Seattle in the biannual players' union salary release on Thursday.)
Seattle is still coming to terms with its place in a shifting landscape. This summer's transfer window, and the offseason beyond, feels pivotal. The Sounders have been beset by injuries and are better than they've shown so far this season, but they are an aging squad in need of fairly substantial turnover.
Wednesday night's surprising 2-1 victory over Toronto at BMO Field brought a reprieve from the big-picture questions and lowered the collective angst. Fielding an experimental 5-4-1 lineup stocked with youngsters and rotation guys rather than any of Clint Dempsey, Osvaldo Alonso and Nicolas Lodeiro, Seattle somehow triumphed in the rematch of the past two MLS Cup finals.
The spirit on display in Toronto is a hallmark of Schmetzer's teams. Even if results aren't going their way, you usually cannot question the effort. His squads are always going to battle and scrap for every inch. Some things never change.
The same goes for Sunday's rivalry match. Faces and figureheads come and go, but the deeper significance of Timbers-Sounders remains constant. This is the one professional sporting outlet between the two biggest cities in the American Northwest. The passion is real. The series' longevity lends it an authenticity that no other rivalry in MLS can match.
Sounders-Timbers is no longer Schmid vs. Porter. But in a sense, it never really was.