SEATTLE -- After they stopped celebrating, the Seattle Sounders admitted this victory meant a little more.
The Sounders finally got the better of the LA Galaxy and knocked off the defending MLS Cup champions.
Erik Friberg took advantage of LA's third massive defensive mistake and scored in the 73rd minute, lifting the Sounders to a 3-2 victory in the knockout round of the MLS Cup playoffs on Wednesday night.
Seattle had been eliminated by LA in the playoffs three times since 2010.
A season ago, the Sounders watched as yellow confetti was sprayed around their home stadium for LA's victory in the Western Conference finals. This time, it was the Sounders turn to rejoice.
"They knew this was a team we needed to get off our backs," Seattle coach Sigi Schmid said.
The Sounders scored twice in the first 12 minutes on goals from Clint Dempsey and Nelson Valdez, part of a wild first half that featured four goals in the first 22 minutes.
But Friberg provided the winner, taking advantage of a third defensive mistake by the Galaxy and sending Seattle into the conference semifinals against either FC Dallas or Vancouver.
"I think Christmas came early in Seattle. We absolutely gift-wrapped that game for them tonight," LA coach Bruce Arena said. "Our play in front of our goal defensively was atrocious tonight."
Sebastian Lletget and Gyasi Zardes scored in the first half for LA, but the Galaxy had just five shots in the second half as Seattle's defense tightened after giving up 11 shots in the first half.
LA had to travel to Seattle after losing at Sporting Kansas City on the final day of the regular season. The Galaxy entered the final day in position to avoid the knockout round, but are now done for the year.
"When you're the champions and you know what it feels like to lift that trophy and it can be taken away from you, it's difficult to take," striker Robbie Keane said.
Friberg's goal started with a cross from Tyrone Mears into the penalty area. The ball was headed by LA defenders A.J. DeLaGarza and Leonardo, but goalkeeper Donovan Ricketts left his net and slipped. The ball fell to Friberg, who put the left-footed shot into the far corner of the net.
"It was perfect," Friberg said. "It's always fun to score a goal, but the important thing is we won."
The Galaxy's best chance late came in the 82nd minute when Zardes' shot from 15 yards was pushed aside by goalkeeper Stefan Frei.
The wild first half featured Seattle letting two leads slip away in the first 22 minutes and having a third goal waived off after a lengthy discussion between officials determined Dempsey was offside and negated Andreas Ivanschitz's goal.
Dempsey scored after a miscommunication between Ricketts and defender Omar Gonzalez, but LA answered quickly. Touch passes from Giovani Dos Santos and Zardes left Lletget unmarked, and his shot beat Frei to the far post in the sixth minute.
Seattle went back in front in the 12th minute when Ivanschitz's free kick from 35 yards found Valdez streaking past Steven Gerrard, and he finished for his second goal with Seattle. Again, the lead lasted just a few minutes, with Zardes pulling the Galaxy even when his shot deflected off Valdez and past Frei.
"The toughest road lies ahead, but obviously [this] is a good feeling," Seattle's Brad Evans said.