Though they once owned a big lead in the Western Conference, the Seattle Sounders have fallen back to the pack in the tight race for first place thanks to their recent scoring drought.
The Portland Timbers haven't had much trouble in that area as they've worked their way back into the playoff race.
As the Sounders look to avoid matching a team-worst road skid, the Timbers will try to extend their five-game home unbeaten streak in this series when these Cascadia Cup rivals square off Sunday night.
The Sounders (13-7-3) appeared to be the best in MLS at the end of June following a 9-1-1 stretch that left them with a league-best 33 goals and a seemingly comfortable 10-point advantage in the conference.
That big lead, however, has faded while the club totaled six goals and was shut out three times during a 2-4-1 stretch.
Seattle fell out of the top spot for the first time in four months before forward Chad Barrett provided his sixth goal of the season and 50th of his career 36 seconds into the second half of Wednesday's 1-all draw with San Jose.
The Sounders are currently in a three-way tie for first with FC Dallas and Real Salt Lake. They trail Vancouver (2-0-1) in the Cascadia Cup race at 1-1-2, while the Timbers are 0-2-1.
"We're going down (to Portland)," Seattle coach Sigi Schmid said. "Points are important to us and they're important to them."
Seattle's Clint Dempsey has a team-high nine goals with four coming against the Timbers, but he's battled fatigue after playing in the World Cup and has been held scoreless in his last five contests.
Dempsey hasn't found the back of the net since a 2-0 home win over Portland on July 13. He also scored an MLS career-high three goals to help Seattle rally from a two-goal deficit in a 4-all tie at Providence Park on April 5.
The Sounders also posted a 3-1 overtime victory over Portland in the quarterfinals of the U.S. Open Cup last month.
"We have to look at things that we've done and had success against them," Schmid said. "And try and do more of that."
Schmid's club will try to avoid matching a franchise record with its fourth straight road defeat. That could be a difficult task at Portland, where they've gone 0-2-3 since winning their first MLS trip in July 2011.
The Timbers (7-7-10) are looking for their season-best third straight home victory as they go for their fourth win in six matches overall. They rank among the MLS leaders with 30 goals since the beginning of May, going 7-4-5 to crawl closer to playoff position.
Maximiliano Urruti has scored a team-high seven times over that span, while Diego Valeri has six goals and eight assists.
Valeri, who has a goal in each of the last two home meetings with Seattle, had his four-game scoring streak snapped in a 1-all draw at New England on Aug. 16.
Liam Ridgewell had his first career MLS goal. He joined Portland on June 25 after signing a designated player contract from the English Premier League's West Bromwich Albion.