The Emerald City side capped a remarkable season turnaround with a vital win to take spot in MLS.
Seattle wasted no time getting on the board, scoring in just the third minute. A nice passing move pulled the RSL back line out of position, and Andy Rose's neat chip back from the endline dropped invitingly for a poorly-marked Obafemi Martins to volley in.
Lamar Neagle made it two before halftime with his third goal in as many games, bringing him to a new career high of eight in a single season. A marauding run brought right back DeAndre Yedlin down the wing and an excess of open acreage allowed him to turn inside and pick out Neagle while Mauro Rosales drew the defense away with a near post run.
Where the Sounders were, at one point, a full 15 points out of first place, the win over RSL sends Seattle top of all MLS and the Western Conference. The Rave Green are now a single point ahead of RSL, but with two precious games in hand.
The Sounders (15-8-4) have now won five in a row, with eight victories in their last nine matches. Real Salt Lake (14-9-6) slips to its first loss in four games.