Clint Robinson and Danny Espinosa hit back-to-back home runs, providing the power for Washington on a day when NL MVP Bryce Harper struck out all four times up.
Scherzer (3-1), who grew up in suburban St. Louis, struck out nine and scattered four singles. He didn't allow a runner past first base, earning his first win in five career starts against the Cardinals.
By finishing the weekend sweep, the Nationals emphatically ended years of frustration at Busch Stadium. It was their first series win in St. Louis since May 2007. Washington improved to 17-7 overall, the best start in club history through 24 games.
