"I could have had some better ABs this series, of course, but I'm just trying to have good at-bats," Harper said. "I'm getting pitches to hit over the plate and sometimes hitting them and sometimes missing them, so I'm trying to be a little more patient."
Harper improved to 9-for-28 in his career against Koehler with six home runs and 11 RBIs. He has now picked up at least one RBI in a career-high eight straight games. The only other player in Nationals history with a streak longer is Ryan Zimmerman, who drove in a run in nine consecutive games Sept. 3-12 in 2012.
But the Nationals' offense managed only one hit after Harper's homer, an infield single from Wilson Ramos to start the second inning, and were unable to capitalize on Harper's fast start.
"It was kind of a flat day. I don't know if it was us or them, but it was kind of a flat day," manager Dusty Baker said. "And this is our first real, long road trip -- not really long, but it's preparing us for the long trip. We've just got to go home and regroup now, and come out swinging against Minnesota [on Friday]."
Jamal Collier is a reporter for MLB.com. Follow him on Twitter at @jamalcollier. This story was not subject to the approval of Major League Baseball or its clubs.