SEATTLE -- Denis Bouanga scored his fourth goal of the MLS Cup playoffs in the 30th minute, goalkeeper Maxime Crepeau made seven saves, and defending champion Los Angeles FC advanced to the Western Conference final with a 1-0 win over the Seattle Sounders on Sunday night.

Bouanga got one chance at goal and didn't miss, scoring in his sixth straight game and sending LAFC home for the conference championship game against the Houston Dynamo next Saturday.

It also kept alive LAFC's hopes of becoming the first back-to-back champion since the LA Galaxy in 2011-12.

Bouanga was the Golden Boot winner during the regular season with 20 goals and he added three more in LAFC's opening round victory over Vancouver. His goal came despite Seattle controlling play for most of the first half and having two great chances in the opening five minutes that were denied by Crepeau.

Bouanga's shot was the only attempt LAFC put on goal in the first half and it finished with only two shots on target in the match.

They were fortunate to have Crepeau on the other end.

The Sounders 19-game playoff unbeaten streak at home came to an end. Seattle had not lost a home playoff match since losing to Portland in the 2013 postseason.

Crepeau's big night started almost immediately as he pushed aside Josh Atencio's left-footed shot from the top of the penalty area in the opening moments. His better save came in the fourth minute when Jordan Morris outran Giorgio Chiellini on a breakaway, but Crepeau quickly left his net and was able to swat Morris' chip attempt.

Seattle pressed in the final 20 minutes and Crepeau answered every attempt by the Sounders, denying shots from distance by Alex Roldan, Joao Paulo and Albert Rusnak's chance in the fourth minute of stoppage time.