Harper's 20th home run of the season, a two-run blast, traveled an estimated 449 feet off Bud Norris in the first inning, according to ESPN Stats & Information. The reigning National League MVP later walked and scored on Wilson Ramos' RBI double.
Ben Revere, Jayson Werth and Anthony Rendon also hit home runs and Trea Turner had an RBI triple and stole home for Washington, which snapped a six-game losing streak to Los Angeles dating to last season. Left-hander Gio Gonzalez (6-8) had one of his best starts of the season, allowing one run on three hits and striking out six in six innings.
Norris (5-8) gave up six runs on seven hits in five-plus innings before giving way to the bullpen. He struck out eight as part of an inconsistent outing, and it didn't help that he allowed three home runs, including back-to-back from Revere and Werth in the fifth.
Harper's rocket was one of the longest hit at Nationals Park, as he took a 3-1 fastball from Norris and sent it over the Jackie Robinson sign on the facade in right. Harper reached 20 home runs for the fourth time in five seasons.
Dodgers: Manager Dave Roberts said surgery was "more of a possibility" for LHP Clayton Kershaw after a setback with the herniated disk in his back. ... LHP Alex Wood underwent arthroscopic surgery on his left elbow and is expected to miss eight weeks. ... Roberts said Seager would be back in the lineup Thursday after missing two games with a stomach virus. ... RHP Chris Hatcher was placed on the disabled list with an oblique injury.
Nationals: Rendon returned to the lineup after missing two games with the flu. ... INF Stephen Drew was out sick again. ... Manager Dusty Baker said RHP Joe Ross (shoulder inflammation) and 1B Ryan Zimmerman (left rib cage sprain) will each go on a rehab assignment at some point.
CALL HIM TREY TURNER
Turner made it back-to-back games with triples when he hit one into the left-field corner in the sixth inning. He then stole home on a botched pickoff attempt, the Nationals' first steal of home since Harper in 2012.
KENDRICK KEEPS IT ALIVE
With his double in the eighth, Dodgers LF Howie Kendrick extended his hitting streak to 12 games. A fly out left him stranded.
Called up earlier in the day, RHP Koda Glover made his major league debut with a perfect ninth.
Information from The Associated Press was used in this report.