Cardinals starter Genesis Cabrera blanked the Reds in the top of the first frame. Reds starter Luis Castillo then settled in against Carpenter to leadoff the bottom of the first inning. Castillo began the exchange with a ball, before heaving in a 96.8 mph fastball.
The Cardinals third baseman smacked the offering over the center field fence for a 413-foot homer. The long ball had an exit velocity of 102 mph, according to Statcast.
Neither National League Central squad plated a run in the third inning. The Reds began their rally in the bottom of the fourth frame. Jose Peraza plated Jose Iglesias with an RBI double for the Reds' first run. Nick Senzel brought in the go-ahead run by plating Peraza on another double two at-bats later.
Yasiel Puig helped Cincinnati get some insurance with a solo home run in the fifth inning. Peraza brought in the final run of the game with an RBI single in the same inning.
Peraza was 2-for-3 with two RBIs, a run scored and a walk in the win. Joey Votto was 2-for-5 for the Reds. No Cardinals hitter had multiple hits in the loss.
Castillo allowed one run and two hits in six innings for the Reds. He now owns a 6-1 record and has a 2.38 ERA this season.
The Reds and Cardinals resume the series at 8:15 p.m. on Wednesday in St. Louis.