Freeman's shot in the first inning put the Braves ahead to stay and he added an RBI single in the third for a 3-0 lead.
Luis Avilan (1-0) earned the win after yielding one hit over 1 2/3 innings in relief of starter Tim Hudson, who allowed three runs on six hits over 4 1/3 frames.
Philadelphia's Cole Hamels (0-1) was roughed up for five runs on seven hits over five innings, striking out five.
Chase Utley provided a solo homer and three RBI for the Phillies.
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