Bryce Harper took Miami Marlins' reliever Kyle Barraclough deep for a two-run blast in the seventh that put Washington up 4-2, but before he put the Nationals ahead, pinch hitter Stephen Drew hit a two-run home that tied the game at 2-2.
It was Drew's second home run of the season, his first as a pinch hitter this season and the Nats' fifth pinch hit home run of the year, the second-highest total in the majors.
After the Marlins pulled within one in the eighth at 4-3, Chris Heisey hit the Nationals' sixth pinch hit home run, behind only the St.