Prince Fielder hit his 20th home run and Corey Hart had three hits and two runs scored for the Brewers.
Mike Burns (1-1) held the Mets to two runs on five hits over 6 2/3 innings to earn his first big-league victory as a starter.
Johan Santana (9-6) gave up six runs on nine hits with four walks in six-plus innings.
David Wright was 3-for-4 with a two-run homer and Fernando Martinez hit his first homer for the Mets, who took their fifth straight loss.
Copyright 2009 by United Press International.