Ruidiaz scored a goal in each half to complete a superb victory for Seattle, who recovered from falling behind to an early Eduard Atuesta goal to reach Major League Soccer's championship game for the third time.

The defeat left Bob Bradley's Los Angeles team shell-shocked after a record-breaking regular season campaign that made them favourites to win a maiden MLS Cup.

However the LAFC's raucous Banc of California Stadium home crowd were silenced by a superbly disciplined Sounders display.

Seattle will now face either Toronto FC or defending champions Atlanta United in the MLS Cup final on November 10. Toronto, who defeated Seattle in the 2017 final, face Atlanta in Georgia on Wednesday.