Devin Mesoraco homered and drove in two runs, and Jay Brucealso homered as the Reds snapped a three-game losing streak and scored more than two runs against St. Louis for the first time in the last seven games between the teams.
Latos (6-0), who got the decision in Cincinnati's last win over St. Louis on April 29, allowed eight hits and two runs with no walks and five strikeouts against a Cardinals team that went into the game leading the National League in hitting.
The Reds, who'd lost five of their last six games against St. Louis, scored four against St. Louis rookie left-hander Tyler Lyons. He gave up six hits and a walk with two strikeouts in 5 1/3 innings before a sellout crowd of 40,740 at Great American Ball Park.
The score was 2-2 when Derrick Robinson, a rookie outfielder making his first career start in the No. 2 slot in the batting order, led off the sixth with a double down the right-field line. Votto followed with a ringing double to straightaway center field. Robinson scored the go-ahead run, and Votto went to third on shortstop Pete Kozma's errant throw to the plate.
Votto couldn't score on Brandon Phillips' groundout to a drawn-in Kozma or on Bruce's swinging bunt infield single. Todd Frazierwalked to load the bases, and Mesoraco grounded a single through the hole into left field for a 4-2 lead.
The Cardinals used fundamentals to take a 1-0 lead in the second. Yadier Molina lined Latos' first pitch to right for a double, went to third base on David Freese's fly out to deep right and scored on Jon Jay's broken-bat groundout to second.
Bruce tied it in the bottom of the inning with his 10th homer of the season, a 382-foot solo shot into the right-field bullpen on a 1-0 pitch with one out.
Carlos Beltran and Allen Craig both extended hitting streaks while giving St. Louis a 2-1 lead in the third. Beltran extended his to nine games with a one-out double to left-center field and moved to third on Matt Holliday's groundout to second. Craig hit a slow bouncer up the middle that shortstop Zack Cozartfielded behind second base, but his hurried throw took Votto off the bag, allowing Beltran to score. Craig was credited with an infield hit that gave him a 12-game hitting streak.
Mesoraco tied it 2-2 in the fifth with his third homer of the season and first since May 21, a 382-foot drive into the right-center field seats on a 1-0 pitch from Lyons.