The English star prevented an open-net goal in the 96th minute of the match before sending a perfect cross to Luciano Acosta for the game-winning score:
Acosta finished with a hat trick in the 3-2 victory, but Rooney transformed the match with his play on both ends of the field.
The 32-year-old transferred to DC United in July after a legendary career in the English Premier League. While this was just his sixth match with his new team, he has already showed what kind of impact he can make in the MLS.
DC United have only five wins in 20 matches all season, but three have come since Rooney joined the club.