Landon Donovan nearly scored for Los Angeles in the 65th minute but his boot from 20 yards out hit the crossbar and kept the margin at one.
Seattle's best chance came in the first half when Erik Friberg shot wide of the right goal post while Galaxy keeper Josh Saunders was out of position. The Sounders best chance at tying the game came in the final 20 minutes when the Galaxy's O'Brian White was able to re-direct a crossing pass inches from the far goal post.
Los Angeles won all four matches against Seattle last season.
UPI horse racing roundup