Chatwood (1-0), recalled from Class AAA Colorado Springs last week, baffled the Dodgers on five hits while making his second start of the season. The right-hander didn't issue a walk and struck out five.
His two-run single highlighted a five-run fourth inning that put the Rockies ahead 10-0.
Wilin Rosario went 3-for-4 with a three-run homer and rookie Nolan Arenado -- playing in just his second major league game -- added three hits, including a two-run shot, in the victory.
Dodgers starter Ted Lilly (0-1) allowed five runs (four earned) on eight hits over three full innings.
Jerry Hairston Jr. knocked in both Los Angeles runs.