Gilmartin, making his second appearance since joining the Rome club last week, worked four scoreless innings of one one-hit ball, and the Braves used a pair of eighth-inning runs to beat the Drive, 3-2, in the fourth game of a five-game series.
It was the Braves’ sixth victory in their past eight games, including winning three of the first four games in this series.
Gilmartin, who was the Atlanta Braves’ No. 1 pick in the June draft, finished with four strikeouts and one walk. He did not factor in the decision.
The victory went to Dan Jurik (1-1), who pitched 4 1-3 innings and allowed two runs on five hits.
Reliever Gus Schlosser recorded the final two outs to earn his seventh save and lowered his ERA to 2.66.
Evan Gattis drove in the go-ahead runs with a two-run single in the eighth inning that broke a 1-1 tie and gave the Braves a 3-1 lead.
Greenville scored one run in the bottom of the eighth, but the Braves held them off in the ninth.
Matt Lipka, Tommy La Stella and Edward Salcedo finished with two each. Salcedo also collected his team-leading 56th RBI for the Braves, who will face Greenville tonight in the series finale before heading to Asheville for a four-game series.