Reds starter Johnny Cueto (12-6) struck out nine and allowed one run in seven innings and Ryan Ludwick drove in two runs. Aroldis Chapman pitched the ninth for his 24th save.
Giancarlo Stanton hit his 25th home run for Miami and Tom Koehler (7-8) took the loss allowing two unearned runs in seven innings.
With the Marlins leading 1-0 in the top of the eighth, the Reds loaded the bases with one out. Todd Frazier flied to right fielder Stanton whose throw to the plate easily beat Zack Cozart for what appeared to be the final out of the inning. After a 6-minute, 10-second instant replay review, the call was overturned because catcher Jeff Mathis was ruled to be blocking the plate, tying the game 1-1.