Potomac jumped out to an early lead thanks to a three-run home run from left fielder Randolph Oduber in the first inning. The Nationals added another run in the second and tacked on a final insurance run in the seventh.
The early runs proved to be enough, however, thanks to Potomac's pitching staff. Left-hander Hector Silvestre struck out six batters and held Myrtle Beach to one run on five hits and one walk in six innings. Right-handers Manny Rodriguez and Gilberto Mendez combined to strike out four batters in three perfect innings to close out the title.
Oduber finished the night 2-for-3 with a walk, a run and three RBIs. Catcher Pedro Severino, the Nationals' No. 12 prospect, added an RBI single and a walk. The 21-year old hit .333/.450/.467 in the playoffs.
Second baseman Tony Renda, the Nationals' No. 18 prospect, went 1-for-3 with a triple, a walk and two runs. After hitting .307/.381/.377 in the regular season to win the Carolina League batting title, Renda hit .304/.385/.435 in six playoff games.
Potomac went 78-58 during the regular season and won the Northern Division in both halves of the season. It swept Lynchburg in their best-of-three semifinal series last week to reach the Mills Cup for the second consecutive year.
This year's Mills Cup had a different ending for Potomac, however. A year ago, it was swept by Salem. Wednesday night, the Nationals celebrated the franchise's fifth Carolina League championship and first since 2010.
Teddy Cahill is a reporter for MLB.com. Follow him on Twitter at @tedcahill. This story was not subject to the approval of Major League Baseball or its clubs.