As rivalries go in American soccer, they don't get any bigger than Seattle and Portland.
Nowhere else can an allotment of 500 tickets prove such an insufficient number for travelling supporters and nowhere else can claim a more grandiose setting than CenturyLink Field or Jeld-Wen Field on matchday.
"It's the best rivalry in the league," Sounders FC head coach Sigi Schmid said without hesitation. "There's a lot of pride at stake for each of the cities and as a result it's a game that brings out the uppermost in emotion for all the players."
The teams met frequently in the North American Soccer League from 1975 until the Timbers dissolved in 1982. Then it was rekindled when the Timbers joined the A-League in 2001 and it remained a bitter competition until the Sounders moved from the second division to Major League Soccer in 2009. Portland would have two more seasons in the second division before joining the Sounders in the top flight in 2011, but they still managed to cross paths with their northwest rivals in the Lamar Hunt US Open Cup in 2009 and 2010, with Seattle winning both meetings in Portland.
Last season, the two meetings were epic confrontations that lived up to the billing as the teams met for the first time at the MLS level.
With both teams struggling in the standings over the last few weeks, this year's match not only holds high importance in the hearts of the fans and the pride of the players, but also to the positioning on the table for the two teams.
"It just continues to grow and get bigger and I think it will continue to gain steam as the teams play each other," said Sounders midfielder Roger Levesque, who played with the Sounders at the USL level from 2003-2008 and has been with the MLS club since 2009. "It's an important game for both clubs on Sunday. A little bit of rough patches for each of us and that's just going to heighten the intensity and really push the rivalry even more."
The heated derby has been decidedly in Seattle's favor in recent years.
Their last loss to Portland came on April 26, 2008, making the Sounders unbeaten in their last six matches against the Timbers, across all competitions. Overall, they haven't lost a season series to the Timbers since 2004.
The Sounders went 1-0-1 against the Timbers last year, coming up with a comeback 3-2 win at Jeld-Wen Field and drawing 1-1 at CenturyLink Field. Additionally, Seattle topped Portland in two US Open Cup meetings in 2009 and 2010, both in Portland prior to the remodel of their stadium.
But just like both team's recent struggles in MLS play, Schmid says that past results don't matter in derby matches once the whistle blows.
"I think this game has its own unique value and it's a result that is independent of how you are doing in your other games because of the intensity that it has and the importance it has to our supporters," he said.
Those supporters will come in droves, too.
Not only is the home crowd expected to be in full voice for the first of three matches between the two clubs this season, but the Sounders will also be bringing 750 fans to Jeld-Wen Field, filling an allotment agreed upon by Seattle, Portland and the Vancouver Whitecaps.
"The atmosphere and the energy in that stadium will be absolutely amazing," Levesque said. "I think there will be a lot of positive energy too with the Sounders fans and the support that they give us. I expect them to be every bit as loud as the Timbers fans. They may be outnumbered a little bit, but they are that much more passionate as a support group."
Last year, that group of 500 travelling supporters – and the many more who found tickets through other avenues – were located behind the Sounders bench, making them feel as close to home as they could in the renovated Portland ballpark.
"I love having our crowd right behind our bench. It drowns out their crowd," said Zach Scott, who experienced the rivalry first-hand since he joined the Sounders in the USL in 2002 and has played 29 matches against the Timbers. "You don't even realize you're playing in an away stadium because they're so loud and so passionate. It's huge for us to get that kind of support. Especially on the road."
With the ESPN cameras broadcasting the match nationwide, the match will act as a reminder of why Seattle and Portland share the biggest rivalry in American soccer.
Later on Sunday, NBC Sports will broadcast the Eastern Conference version of a rivalry when the New York Red Bulls meet DC United. However, former Red Bull Jeff Parke notes that the New York-DC rivalry can't hold a candle to the Cascadia matches.
"It's nothing like this. You always hated playing against them and wanted to beat them so bad. Here there's so much history," Parke said. "If every team had a rival like this, it'd be awesome. I don't know how any sort of sports fan couldn't get excited about it."