Every rivalry has a power dynamic. One team is almost always bigger and generally better than the other. That ebbs and flows with time, but both involved parties tend to recognize this overall reality.
When it comes to the Seattle Sounders and Portland Timbers, there really is no question which club is "bigger" in that sense. The Sounders have won more than half the all-time encounters (holding a 42-29-9 advantage), have earned ten major trophies (dating back to NASL), are a regular participant in the MLS Cup playoffs and average crowds that are about twice as big as those that grace Jeld-Wen Field.
The first two years of the two teams being in MLS has pretty much followed that script. Most of the games have been highly competitive, but there was rarely any doubt as to who was the "better" team by the end of the season.
This year has been different, and that could potentially take this rivalry to a new level.
Most of the credit for this new dynamic is Timbers head coach Caleb Porter. During the Timbers' first two years of their MLS existence, there was a fair amount of big talk but very little to back it up. The team was saying all the right things about not only meeting the standard set by the Sounders, but surpassing it. Making the playoffs in Year 1 was absolutely a goal. Making the playoffs in Year 2 was seen as a must. Neither ended up happening, and this season was expected to be more of a rebuilding year.
To Porter's credit, he doesn't seem to have made any promises beyond getting the Timbers headed in the right direction. With the Timbers just three points shy of the Supporters' Shield heading into Sunday's game against the Sounders, it's safe to say he's done that.
He's also saying all the right things about not allowing his team to put too much emphasis on this single encounter.
The Sounders, meanwhile, have been enduring a roller-coaster season that has seen them unable to field a consistent lineup for various reasons. A five-game winless start has been overcome and the team is still in position to make a run at the Shield themselves, but the season has so far been defined by big losses on the road to teams like the LA Galaxy and Real Salt Lake.
Perhaps because of this up-and-down season, the Sounders are embracing the "bigness" of the game. Sounders coach Sigi Schmid wants his players to feed off the crowd and the players talk about how important this game is to the fans, as well as themselves.
Schmid has also talked about wanting to re-establish themselves as the top dogs in this rivalry.
Even after this game, each team will have about a quarter of their season left to play. There will be plenty of time to ultimately change the year's narrative. But there's also a growing sense that the Sounders are going into this game with the attitude that it is a "must-win."
Maybe that's natural. The Sounders are at home. They'll have the crowd behind them. They need to make up ground in the standings. A big win could very well send them to the heights that have so far eluded them in MLS.
But there's also a sense that they know losing this game could really sway the larger dynamic of the rivalry, if even only for a short time. The Timbers are almost playing with house money at this point. Porter has admitted that he didn't think the turnaround would happen this quickly. Winning on Sunday, in front of a massive crowd that will be quite hostile, would almost certainly be the biggest win in the Timbers' MLS history and one of the memorable one's ever. It might even be big enough to flip the entire narrative on its head.