The Chicago Cubs rediscovered their offense at Wrigley Field, and Jake Arrieta stifled the St. Louis bats in his return from the minors.
Nate Schierholtz drove in three of Chicago's runs in a 7-0 victory.
The Cubs entered Friday's series opener having been shut out in four of their last five home games, but capitalized on Cardinals starter Jake Westbrook's early wildness to score three first-inning runs.
Donnie Murphy and Darwin Barney also had an RBI for Chicago, which snapped a four-game skid that began with Sunday's setback at St. Louis and notched just its second home win in 13 tries.
Arrieta (1-0), recalled from Triple-A Iowa to make his second start with the club since being acquired from Baltimore on July 2, surrendered only two Carlos Beltran hits and struck out seven over seven innings.
"I think the atmosphere at Wrigley is going to be pretty intense every time I take the mound," Arrieta said. "I know all about the rivalry and it's something I'm excited to be a part of."
Westbrook (7-8) lost his fifth consecutive road start after allowing seven runs -- six earned -- on eight hits and five walks in 6 2/3 innings.
"It's not what any of us were looking for. He had trouble finding the release point for his sinker," Cardinals manager Mike Matheny said about Westbrook. "He just couldn't find the feel for it."
The right-hander struggled with his command at the onset of the game, issuing three consecutive walks to load the bases with no outs. Schierholtz then plated a pair with a single to center field and a two-out base hit by Murphy brought home Anthony Rizzo.
Chicago added to its lead by scoring in three straight frames, beginning with a Schierholtz sacrifice fly in the fifth.
Barney hit an RBI double in the sixth and scored later in the inning on an Arrieta bunt before a second wild pitch by reliever Sam Freeman enabled Rizzo to scurry home in the seventh.
Chicago optioned pitcher Eduardo Sanchez to Iowa to clear room on the roster for Arrieta, who made his Cubs debut on July 30 ... Cubs reliever Matt Guerrier had surgery Friday to repair the flexor mass in his right arm and will be sidelined 6-to-8 months ... St. Louis second baseman Kolten Wong made his major league debut, going 0-for-3. Wong, the team's first-round pick in 2011, became the first Hawaiian to play for the Cardinals since Joe DeSa in 1980 ... St. Louis left fielder Matt Holliday went 0-for-4 to halt his hitting streak at 12 games.