The Nationals prospect scattered six hits and struck out four over seven innings to pitch Potomac to a 2-0 blanking of the Salem Red Sox at Pfitzner Stadium.
Holder (3-7) retired his final six batters to win for the first time in four starts since May 21. He benefited from three double plays, including an unusual one turned in the fourth inning.
After Wilfredo Pichardo led off with a single, Peter Hissey dropped down a bunt for a hit. First baseman Justin Bloxom alertly fired to third baseman Jose Lozada to cut down Pichardo. Lozada also nailed Hissey trying to take second.
Hector Nelo recorded the final five outs, fanning one, to earn his eighth save.
A 2009 third-round Draft pick out of the University of Georgia, Holder entered with a 2-7 record and 7.05 ERA in 12 Carolina League starts. In his last start on June 6, he surrendered eight runs on seven hits over five innings against Frederick.
Holder was a South Atlantic League All-Star last season at Class A Hagerstown, going 4-3 with a 3.15 ERA in 12 starts. He earned a promotion to Potomac, where he was 3-3 with a 4.09 ERA in 15 games, including 14 starts.
J.P. Ramirez was 2-for-4 with a double and a run scored, while Destin Hood collected three singles for the P-Nats.
Jun Tawaza continued his comeback for Salem and did not figure in the decision after allowing two hits and striking out three over four shutout innings.