Harper's shot came in the bottom of the seventh inning, and was the Nationals' first run of the afternoon. They were down 3-0 at the time.
Harper's home run was followed two batters later by a Asdrubal Cabrera home run that brought the Nationals one run closer to tying the game. But the Giants held on to win 3-2.
The Nationals and Giants are facing off in the National League Division Series. Game 2 is Saturday afternoon in Washington..