Buddle, Major League Soccer's leading scorer, has nine goals in six games for the Galaxy (5-0-1), off to their best start since 1998 when they won their first nine games.
Philadelphia (1-4), which has yet to win on the road, extended its overall losing streak to four games in MLS and U.S. Open Cup play.
A.J. DeLaGarza put Los Angeles ahead 53 seconds into the game by sliding to convert Buddle's cross from the left side of the penalty area into a 5-yard shot.
Buddle extended the lead with two goals in 18 minutes. In the 27th minute, after Union goalkeeper Chris Seitz deflected Alan Gordon's diving 7-yard header, Buddle secured the rebound and scored from 7 yards. Then in the 45th minute, Buddle took Landon Donovan's pass and scored from 15 yards inside the left post.
Donovan's assist was the 80th of his MLS career, tying him with Mauricio Cienfuegos and Chris Henderson for seventh place. Philadelphia's Jack McInerney ended the scoring in the 84th minute with his first MLS goal, a diagonal 16-yard shot that Fred set up with a solo run.
Philadelphia played with 10 men after Stefani Miglioranzi received a red card in the 45th minute.
The Galaxy's Clint Mathis, who played for the United States in the 2002 World Cup, made his season debut when he replaced Gordon in the 70th minute.
Philadelphia's Kyle Nakazawa made his professional debut by coming in for Andrew Jacobson in the 61st minute.
Sebastian LeToux, Philadelphia's leading scorer with four goals, missed the game after spraining a ligament in his left knee Tuesday night in a U.S. Open Cup qualifier.
(Copyright 2010 Philadelphia Union. Reprinted by permission)
