Seattle Sounders 1, Vancouver Whitecaps 4

Martin Rennie knows what kind of talent he has in young Vancouver striker Kekuta Manneh.

The question with an 18-year-old is whether there will be consistency and poise to go along with the skill.

''We talked about it before that if he showed up, he could make a big impact, and he did,'' said Rennie, Vancouver's coach.

Manneh recorded the first hat trick of his MLS career and the Whitecaps kept their playoff hopes alive with a 4-1 win over the suddenly slumping Seattle Sounders on Wednesday night.

Manneh took advantage of breakdowns in Seattle's back line for goals in the 12th, 42nd and 54th minutes.

Vancouver (12-11-9) denied Seattle a chance to clinch the Cascadia Cup - the regional rivalry between the Sounders, Whitecaps and Portland Timbers.

Seattle (15-10-6) must win Sunday at Portland to claim regional bragging rights, otherwise it'll go to Vancouver.

The loss was Seattle's first at home since dropping the season opener to Montreal back in March and could be a significant blow to the Sounders' chances of winning the Supporters' Shield for most regular-season points in the league.

It marked just the second time Seattle had allowed four goals at home in an MLS match and came after its defense was exposed in a 5-1 loss at Colorado last Saturday.

''It's just unacceptable the last two performances,'' Seattle coach Sigi Schmid said.

Manneh's hat trick was the first for Vancouver since the franchise joined MLS in 2011.

The win also set a franchise mark for most victories in a season (12), but the Whitecaps still trail in the race for one of the final playoff spots in the Western Conference.

''I always have this feeling every game that I'm going to make an impact,'' Manneh said. ''Whether I start or come from the bench, I'm always looking to make an impact.

Nigel Reo-Coker added his first goal of the season on a counterattack in the 82nd minute as Seattle pushed forward, a shot that went through the arms of Seattle goalkeeper Michael Gspurning.

''It's now so many things that I could talk half an hour here maybe. As a whole group we failed in both games,'' Gspurning said.

Clint Dempsey returned from a hamstring injury for Seattle that kept him out since Sept. 13 when he entered in the 51st minute.

Dempsey was left off the U.S. national team for upcoming qualifiers against Jamaica and Panama, while Seattle teammates Eddie Johnson and Brad Evans were called in.

Seattle remained one point behind Real Salt Lake for the top spot in the Western Conference.

''I've been hurt so I haven't been able to impact the game on the field,'' Dempsey said. ''Tonight was the first 45 minutes I've had in a while and for me it was about going out there and seeing where I was fitness-wise and there is some stuff I still need to work on.''

Manneh's opening goal came when Seattle defender Jhon Kennedy Hurtado made a poor header clearance right at Vancouver's Daigo Kobayashi. Manneh raced past Hurtado, collected the pass from Kobayashi and slid a right-footed shot past Gspurning.

Later in the half, Hurtado and Djimi Traore let Manneh run unmarked and Camilo Sanvezzo's pass found Manneh for his second goal.

Manneh's final goal came on another careless giveaway by Seattle's defense in the opening moments of the second half.

''What he's got is what other players his age don't have is to slow down and be calm and finish his chances tonight,'' Rennie said. ''He finished every chance he had.''

Seattle scored in the 69th minute when Mauro Rosales got his fourth goal of the season off a scramble in the penalty area.

Moments later, Seattle had another scoring chance on a quick counter, but DeAndre Yedlin shot late and Vancouver goalkeeper David Ousted was able to make the save.

''I think we have to look at everything. ... The performance of the team has not been good enough,'' Schmid said.

San Jose Earthquakes 1, Colorado Rapids 0

Chris Wondolowski scored his 10th goal of the season in San Jose Earthquakes' victory against the Colorado Rapids on Wednesday.

The win moved sixth-place San Jose (13-11-8) within a point of both Colorado (13-10-9) and the L.A. Galaxy (14-11-6), who hold the last two playoff spots in the Western Conference.

Colorado kept Wondolowski off the scoreboard with multiple saves before the reigning league MVP broke through in the 69th minute, snapping a powerful header from a Shea Salinas corner kick that left Rapids goalkeeper Clint Irwin flat-footed.

It was the league-leading seventh game-winning goal for Wondolowski, who has reached double digits in league scoring for four straight years.

San Jose improved to 4-0-1 in its past five matches as the 2012 Supporters' Shield winners attempt to reach the postseason. The Earthquakes extended their unbeaten streak at home to 15 matches.

The Earthquakes had eight corner kicks to Colorado's two, keeping the Rapids' defense under pressure for much of the match.

Alan Gordon almost put San Jose ahead in the ninth minute with a header off a corner kick that crashed against the post and away from Colorado's goal.

Colorado defender Drew Moor delivered goal-line saves against Wondolowski and Gordon in the 64th minute.

Irwin smothered Wondolowski's shot in the 51st minute, then made a diving left-handed stop to deflect Wondolowski's redirection of a free kick in the 69th minute. Wondolowski scored off the ensuing corner.

The Rapids, who finish with a home-and-home series against Vancouver, still control their playoff destiny. The Earthquakes still need help even if they close the season with victories against the Galaxy and FC Dallas.

Houston Dynamo 0, Sporting Kansas City 0

Jimmy Nielsen had five saves, while Tally Hall had one stop as Sporting Kansas City and the Houston Dynamo played out a goalless draw.

The draw extends Houston's unbeaten streak to five games, but the Dynamo (13-10-9, 48 points) were unable to close the gap on Kansas City (15-10-7, 52 points), which remained four points ahead of the Dynamo in second place in the Eastern Conference.

Nielsen was tested early by the Dynamo.

Will Bruin had a shot from the right box stopped by a sliding Nielsen in the second minute, and Nielsen got a foot on a Bruin shot from outside the right goalkeeper's box in the sixth minute.

Corey Ashe let loose a shot from 30 yards in the middle of the field in the seventh minute that Nielsen had to jump up and bat over the crossbar.

Aurelien Collin kept the game scoreless at the half, clearing a Brad Davis free kick from outside the upper right box off the end line.

Off a throw-in, Kansas City had one of its best chances in the 67th minute, but Dominic Dwyer's header from the penalty area was saved by Hall.