Mike Magee chose an opportune time for his first career hat trick.
With David Beckham now playing for French club Paris-St. Germain and Donovan not expected to return until later this month, the Galaxy was lacking in star power.
But Magee filled the void with only the second multi-goal game of his 11-year career.Magee gave the Galaxy the lead in the 38th minute, firing a left-footed shot past goalkeeper Sean Johnson off an assist from Todd Dunivant.
In the 68th minute, Keane was in front of the net when he passed to right side and found Magee, who drilled it into the high left corner.
Magee scored his final goal less than five minutes later on a shot from the right side after Johnson blocked a shot by Keane.
Keane added the final goal in the 78th minute.