The Chicago right-hander struck out 10 over seven scoreless frames in which he allowed just three hits and a trio of walks as Chicago picked up the win in the rubber match of the three-game set at Turner Field.
Arrieta (11-5, 2.52) was staked to an early lead, with the Cubs scoring three of their four tallies in the first three innings.
First, it was Jonathan Herrera driving in a pair of runs with a two-run single against Braves starter Shelby Miller in the top of the second. One inning later, outfielder Jorge Soler took the Atlanta right-hander deep for his fifth home run of the season.