With fans in the stands, it's hard for visiting teams to earn points at Portland's Providence Park or Seattle's CenturyLink Field.
Without fans, however, the longtime Cascadia Cup rivals have each defeated the other on the road since the resumption of the MLS regular season.
The teams will meet again Wednesday night in Portland.
The Western Conference-leading Sounders (6-2-3, 21 points) are 4-1-1 since returning home from the MLS is Back Tournament, outscoring opponents 19-6 in that span. They're coming off a 3-0 victory last Friday against visiting Los Angeles FC, as Nicolas Lodeiro scored on a pair of first-half penalty kicks and Raul Ruidiaz added a late goal.
"We are not satisfied," Ruidiaz said after the victory. "We want to be able to repeat that (2019 MLS Cup championship) experience."
In their first game after the MLS tourney in Florida, the Sounders won 3-0 at Portland on Aug. 23 as Ruidiaz scored twice.
The Timbers (5-4-3, 18 points), who claimed the title at the MLS tourney, earned a measure of revenge with a 2-1 victory on Sept. 6 in Seattle as Felipe Mora netted the winner in the 83rd minute.
Portland is coming off a 6-1 victory Saturday at San Jose, as Diego Valeri had two goals and an assist in the second game of a series. The Earthquakes and visiting Timbers played to a 1-1 draw last Wednesday.
"It's been a tough week," Valeri said after the most recent match. "But gladly Gio (coach Giovanni Savarese) gave us a day off (Sunday) so we are going to rest well. ... We know that we have a game coming soon, but it's going to be very important for us mentally to be disconnected a little bit, to disconnect and get out some stress and prepare for the next game. We're obviously enjoying being with the family and being back in Portland and resting for the next game."
--Field Level Media