Joao Plata put the Royals on the board, but it was Nick Rimando's late denial that sealed three points.
New Salt Lake signing Luke Mulholland thought he had scored with a 76th-minute poach from short range, but it was called back, much to RSL's chagrin and vocal protests.
The Claret-And-Cobalt wouldn't have long to wait, however. A slide-rule through ball from Kyle Beckerman sprung Joao Plata past the LA defense, and the Ecuadorian slotted home to give the visitors the 1-0 lead.
The Galaxy's chance would come in extra time, but the Galacticos were unable to capitalize. Striker Rob Friend theatrically drew a penalty off of Tony Beltran, but Robbie Keane -- fresh off a new contract -- found his shot pushed wide by Rimando.