The 24-year-old Latos was 4-0 with a 2.27 ERA over his last seven starts and set career highs in starts (34) and innings (209 1-3).
"Pitching against a team like them, they're aggressive, they know what they're doing," Latos said. "A great hitting ballclub. To give up one run in five innings is doing pretty well."
With what was left of an announced crowd of 39,644 standing and hooting, Aroldis Chapman worked the ninth for his 38th save in 43 chances. He has allowed just one hit in four scoreless appearances covering four innings since returning from a nine-game absence due to shoulder fatigue on Sept. 21.
Carpenter gave up three runs and seven hits in six innings while losing for the fifth time in 19 career decisions against Cincinnati. He had seven strikeouts, two more than his total for the first two starts over 11 innings.
The Cardinals stranded two runners in the second and third against Latos and had two on with one out in the seventh before Sean Marshall got pinch-hitter Shane Robinson to fly out and Jon Jay on a broken-bat groundout.
Rolen, batting .247 but hitting at a .301 clip since the All-Star break, tied it in the fourth when he jumped on a first-pitch hanging breaking ball for his eighth homer.
Baker played for keeps in the early going. He brought the infield in with a runner on third and one out in the first for Matt Holliday, who hit a sacrifice fly, then intentionally walked eighth-place hitter Pete Kozma with two outs and a man on third in the second inning to get to Carpenter, who grounded out sharply to third.
NOTES: Carpenter has 1,085 strikeouts with St. Louis, six more than Bob Forsch for third on the franchise list. Next is Dizzy Dean at 1,095. ... Reds pinch-hitter Todd Frazier grounded out sharply with two on to end the sixth, dropping him to 6 for 12 with three RBIs in that role. ... Joey Votto doubled and walked twice and has a major league-leading .515 on-base percentage with 27 walks since returning to the lineup Sept. 5. ... Jay had two hits and has 37 multihit games on the year, 21 of them since Aug. 6. .. Holliday has consecutive multihit games, giving him 55 on the year.