Colorado scored four times in both the second and fourth innings to provide plenty of support for Chatwood (7-3), who held the Brewers to two runs on six hits in seven innings.
Chatwood's double came in the second and a key error with the bases loaded by Milwaukee first baseman Yuniesky Betancourt set up the Rockies' outburst in the fourth.
Wily Peralta (7-10) endured the loss, allowing five earned runs on seven hits in 3 2/3.
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