(AP Photo/Francis Specker)
The Dodgers won for the seventh time in nine games, giving themselves plenty of breathing room this time. Their six previous wins were all by one run, with four coming in walk-off fashion.
Carlos Monasterios (3-0) allowed three runs and four hits in six-plus innings, walked three and struck out none.
St. Louis slugger Albert Pujols was hitless in four at-bats, while Matt Holliday was hitless in three.
Blake Hawksworth (0-3) gave up six runs and seven hits in four innings, struck out five and walked three in his first major league start after 48 career relief appearances.
DeWitt's three-run homer on a 3-2 pitch from P.J. Walters hit the right field pole, extending the Dodgers' lead to 10-1. Ronnie Belliard singled in the other run in the fifth.
DeWitt's bases-loaded sacrifice fly in the seventh made it 11-4 before pinch-hitter Garret Anderson's RBI double brought in another run.
Los Angeles scored four runs in the fourth to break the game open. DeWitt and A.J. Ellis, starting for Russell Martin, had RBI singles, while Rafael Furcal's ground-rule double bounced on the warning track in right field, scoring two runs for a 6-1 lead.
The Dodgers opened the game with a pair of runs in the first. Matt Kemp hit an RBI single and scored on a double-play grounder by Manny Ramirez.
Ryan Ludwick homered twice for the Cardinals, his first coming in the second and his other leading off the seventh. Kemp leaped to snag the ball over the fence in center field, but it narrowly missed his outstretched glove.
* Cardinals 3B David Freese sat out his second straight game because of a sprained right ankle and isn't expected to return to the starting lineup until Friday.
* Cardinals CF Colby Rasmus was out of the starting lineup because of tightness in his left calf a day after he left early against Milwaukee.
* The Cardinals turned three double plays.
* St. Louis fell to 7-1 on Mondays this season, losing on the first day of the week for the first time since July 20, 2009, at Houston.
* The teams played for the first time since Los Angeles swept St. Louis in three games to win the NL division series last October.