The Sounders, playing without the injured Clint Dempsey, struck first, with Johnson getting free in the box and putting a header past Jaime Penedo off a Mauro Rosales corner kick in the 25th minute. It was Seattle's first goal on the road in its last four matches against Los Angeles.
The Galaxy, playing without Landon Donovan, who was a late scratch with a hamstring injury, evened it up when Juninho's free kick over the wall dipped into the bottom left corner of the net for his first goal this season.
Neither team was able to forge a lead in the second half despite multiple chances, so Seattle was left with 50 points, two clear of second-place Real Salt Lake for the best mark in the league, and Los Angeles improved to 45 points while staying in fifth place in the West.
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