After opening his pro career with a pair of singles in his first two at-bats Thursday, the top pick in the 2010 Draft was retired in his next nine at-bats, striking out three times.
Harper ended the skid with a single up the middle in the first inning. After striking out to lead off the fourth and grounding out to end the fifth, the 18-year-old walked in the seventh.
With the Suns trailing in the ninth, 6-3, Harper delivered a bases-loaded single that plated Michael Taylor. After Randolph Oduber was hit by a pitch to force home a second run, Mills Rogers plated two with a single to give Hagerstown a 7-6 edge.
Harper is 4-for-15 (.267) with three RBIs in four games. All four of his hits have been singles.
Blake Kelso collected three singles for the Suns while Taylor tripled, walked and scored three times.
The Braves let a strong start by left-hander Ronan Pacheco fall by the wayside. The 6-foot-6 Dominican yielded two unearned runs on five hits over five frames. He fanned a pair and walked one.
Left fielder David Rohm led the Rome offense with a double, two singles and three RBIs.
Chad Jenkins (1-0) earned the win with 1 1/3 scoreless innings of relief while Sam Brown tossed a perfect ninth for his first save.
Wesley Alsup (0-1) took the loss for Rome after allowing four runs on three hits and a pair of walks over two frames. He struck out three.
The Suns completed a four-game sweep of the Braves to stay perfect this season. Their margin of victory was just one run in three of the four wins.