One of these two Pacific Northwest rivals has featured in each of the last seven MLS Cups, with Portland beaten on penalties by NYCFC back in December.
However, right now, both currently find themselves below the Western Conference play-off line, making three points paramount for both.
When the two met in June, the Timbers enjoyed an emphatic 3-0 victory at Lumen Field.
However, since then, Giovanni Savarese’s side have only won once in seven attempts.
In fact, Portland have lost back-to-back away games coming into this one, beating 3-1 at Toronto and then 4-1 at Sporting Kansas City.
So, Seattle Sounders will fancy their chances of a victory on the road on Oregon.
Brian Schmetzer’s team came from 2-0 down to lead 3-2 at LA Galaxy last Friday night, before conceding a 93rd minute penalty in Carson.
Kelyn Rowe, Raúl Ruidíaz and Jordan Morris on target; the Peruvian has now scored in seven successive games against LA, the first player to achieve this for 21 years.
However, that point isn’t much good to the CONCACAF Champions League winners, who’d actually lost six of their last eight MLS matches.
This means the Rave Green are ninth in the west, above their Cascadia Cup rivals on goal difference alone.
Who will claim three massive points at Providence Park?