One of the premier rivalries in MLS, whenever the Portland Timbers and Seattle Sounders share the field, the league watches. Starting well before the league came to existence, it's one of the league's oldest rivalries.
Ahead of the next edition, as part of Heineken Rivalry Week, here's a look back at how Timbers-Sounders grew into such a great rivalry.
Roots of the rivalry
Originating in the days of the North American Soccer League in the 1970s, and continuing through lower divisions before both were awarded MLS franchises, it's been a long time of animosity in the Pacific Northwest.
The Sounders joined MLS in 2009 while the Timbers followed in 2011. With a few Open Cup clashes and history behind it, the rivalry was fast-tracked, but the Timbers decided to fuel the fire a bit, paying for a billboard just outside of the Sounders' stadium just ahead of their MLS entrance, reading: "Portland, Oregon, Soccer City USA 2011" with the Timbers logo.
Billboards be damned, nothing off the field tops what happens between the lines for these rivals.
A match dubbed "The Red Card Wedding", including Clint Dempsey ripping up a referee's notebook, is always top of the list.
Of course, there was last year's epic playoff series as the Timbers marched to MLS Cup finals, not before some penalty confusion.
STORY_ Timbers final whistle confusion
There have been some incredible tifos, too.
The best Sounders, Timbers tifo in MLS - which is your favorite?
MLS regular season series
This season's series culminates on Friday (10 pm ET | ESPN, TVAS) at Providence Park. Here's how the season-by-season results have gone.
2011: The first MLS iteration of the rivalry went to the Sounders, with a win and a draw in two matches. Alvaro Fernandez scored the rivalry's first MLS goal.
2012: Seattle and Portland evenly split the three matches -- a win each plus a draw -- though the Sounders enjoyed a superior goal difference thanks to a 3-0 victory at CenturyLink.
2013: The two sides again split the three matches and even the goal difference, with both earning 1-0 victories.
2014: This season saw the clubs come together for their highest-scoring season, combining for 16 total goals across three games, with the Sounders taking two wins and a draw. The tie ended 4-4, with Clint Dempsey scoring a late brace to earn a point.
2015: Seattle took the 2015 season series, too, with two wins and a draw again. The Timbers would have the last laugh, winning MLS Cup.
2016: Portland wouldn't hold the MLS Cup superiority over Seattle for long, as the Sounders hoisted the trophy in 2016. Along the way, though, Portland won the season-series with two wins out of three.
2017: Two of the three matches ended in draws, with Seattle winning the other 1-0.
2018: Last season, Portland took two out of three from Seattle, including a wild 3-2 win at CenturyLink Field.
2019: This season, the Timbers went on the road and beat the Sounders 2-1 behind a Brian Fernandez brace. What will Friday have in store?