Piazza has 383 career homers, putting him 49th in the history of the majors. He moved past Jim Rice and Frank Howard with his two home runs Friday night.
New York won for the fifth time in six games with Mike Cameron adding a two-run homer and David Wright a solo shot.
Milwaukee had won seven games in a row.
Piazza hit home runs in each of the first two innings, both of them solo affairs.
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