The Reds also snapped St. Louis' five-game winning streak.
The game was delayed 2 hours, 32 minutes in the middle of the sixth inning by rain and severe weather.
Jay Bruce had three hits and two RBIs. His single in the sixth off Cardinals starter Brad Penny (3-1) brought in Joey Votto with the tying run. One batter later, Jonny Gomes gave the Reds a 3-2 lead with a single.
Cincinnati starter Johnny Cueto (1-1) gave up two runs in five innings. Francisco Cordero pitched the ninth for his ninth save in 10 chances. He gave up a two-out double to pinch-hitter Joe Mather but then got Tyler Greene on a game-ending grounder.
In Philadelphia, New York's winning streak reached eight games as Rod Barajas homered twice to help beat Philadelphia.
David Wright and Jeff Francoeur also homered for the Mets, riding their longest winning streak since a 10-game run in 2008.
New York starter Jonathon Niese (1-1) pitched seven impressive innings, shutting down Philadelphia's powerful lineup, allowing only one run and matching a career high with seven strikeouts.
He yielded Carlos Ruiz's RBI single in the second, then retired 14 straight until a single leading off the seventh.
Wright and Francoeur connected during a three-run second inning against Kyle Kendrick (0-1).
In Miami, Ryan Zimmerman homered twice as Washington defeated Florida for a third straight victory.
Back after a week out with a hamstring injury, Zimmerman quickly made up for lost time, connecting both times on a full count against starter Marlins starter Ricky Nolasco (2-1). Nolasco only last four innings.
Nationals starter Scott Olsen (2-1) pitched six scoreless innings to get his first win in four starts against his former club.
In San Francisco, Barry Zito improved his record to 4-0 for the first time in his career, steering San Francisco past Colorado.
Zito settled down after falling behind 1-0 in the first and lasted eight innings. He followed an impressive effort against St. Louis last Saturday with another solid start, and has yet to give up a home run in 2010.
Aubrey Huff hit a two-run double and Juan Uribe had a two-run single for the Giants off Rockies starter Aaron Cook (1-3).
In San Diego, Clayton Richard pitched six neat innings to guide San Diego over Milwaukee.
Richard (1-2) tied his career high with eight strikeouts and combined with three relievers for San Diego's fifth shutout, tops in the majors, and second straight against Milwaukee. The Padres have thrown 24 consecutive scoreless innings.
San Diego has won 12 of 14 and is in first place in the NL West heading into May for the first time since 1998.
Scott Hairston entered in the seventh as part of a double switch and homered off Dave Bush (1-2) in the bottom half after his brother, Jerry, hit a leadoff double.
The Padres won their eighth straight home game. Their 9-2 home record is the best in the NL.
Milwaukee lost for the seventh time in eight games and has been held scoreless in 22 straight innings.
In Chicago, Alfonso Soriano hit a three-run homer and Chicago connected for four in all while rallying to beat Arizona.
Kosuke Fukudome, Geovany Soto and Marlon Byrd added solo shots as the Cubs shook off a 13-5 beating by the Diamondbacks in the previous game and stopped a three-game skid.
The big blow was Soriano's three-run drive off Rodrigo Lopez (1-1), capping a four-run sixth that put Chicago ahead 6-4 and made a winner of Randy Wells (3-0). The Cubs broke it open with three in the seventh, getting two bases-loaded walks.
Chris Snyder homered for Arizona.
In Los Angeles, Andre Ethier jump-started the Dodgers' offense with a two-run homer, sparking Los Angeles to victory over Pittsburgh.
James Loney added a three-run shot. Both Los Angeles homers came off Pirates starter Charlie Morton (0-5), who has allowed seven in 19 1-3 innings this season and has an ERA of 12.57. He gave up six runs - three earned - in six innings.
Dodgers starter Chad Billingsley (2-1) allowed two runs over six innings to help L.A. snap a five-game losing streak.
In Atlanta, Jason Heyward hit a tiebreaking, two-run homer to lift Atlanta over Houston and end a nine-game losing streak.
Heyward homered for the second consecutive night to break a 2-2 tie and Nate McLouth also went deep against Brett Myers (1-2).
Braves starter Tommy Hanson (2-2) pitched eight innings, giving up two runs in the second inning and then retiring 20 of his last 21 batters. He struck out seven without a walk.
