John Thomson (13-8) pitched seven innings, allowing just one run on five hits as the Braves reduced their magic number for winning the National League East to three.
Thomson won his third straight start, also setting a season high with nine strikeouts. The righthander is 7-1 in his last 14 starts.
John Smoltz earned his 40th save of the season and 150th of his career, despite a shaky ninth. Eli Marrero scored twice and drove in a run for the Braves, who could clinch their 13th straight division title as early as Thursday.
Marcus Giles singled in a run against Reds starter Brandon Claussen in the bottom of the second inning and Eddie Perez' RBI base hit in the third gave Atlanta a 2-0 lead.
Swim Week Miami Beach 2014 [PHOTOS]