Duda hit a tie-breaking, pinch-hit homer in the eighth inning and the Royals survived a shaky ninth to beat the first-place Braves 5-4 on Tuesday night.
Alex Gordon also homered for the Royals and drove in two runs. Both starters - Atlanta's Dallas Keuchel and Kansas City's Danny Duffy - went six strong innings with double-digit strikeouts but didn't factor in the decision.
With the game tied at 2, Royals manager Ned Yost needed a pinch-hitter to start the eighth against Anthony Swarzak, who had a sparkling 0.42 ERA since coming to the Braves in May.