Gio Gonzalez outpitched Cliff Lee, as Washington used a healthy dose of the long ball to subdue Philadelphia, 5-1, in the third edition of a four-game set.
Gonzalez (7-3) worked seven innings, scattering a Darin Ruf solo homer among six hits, while walking two and fanning five.
Meanwhile, Lee (10-3) was deprived his ninth straight positive decision, tagged for four runs -- solo homers by Anthony Rendon, Wilson Ramos, Ryan Zimmerman and Jayson Werth -- on nine hits with six strikeouts over seven full frames.
"All four of the home runs I felt I gave up were decent pitches," Lee said. "It's just one of those deals when it's hot this time of the year here the ball carries."
Rendon scored twice and Ian Desmond added two hits for the Nationals, who recovered from a pair of losses to kick off the series.
Carlos Ruiz posted a pair of hits for the Phillies, whose three-game win streak came to a halt.
Rendon snapped the scoreless deadlock with his leadoff shot to left in the fifth, and Ramos bounced a ball off the top of the wall in right in the following at-bat for a 2-0 game.
The Phils had two runners in scoring position in the home half, but failed to dent the scoreboard.
Zimmerman's long shot to left center to start the sixth provided a three-run cushion to the visitors and Werth followed with a line-drive to left for a 4-0 contest.
"He's a tough guy to get some runs off," Gonzalez said of Lee. "It's good to see your team go out there and battle and do what they did."
Ruf's two-out homer to right in the seventh sliced the Phils' deficit to three, and Ruiz added a single. Pinch-hitter Kevin Frandsen then bunted for a hit, but Ben Revere flied out to deep right to end the inning.
Washington tacked on another run in the ninth. Rendon doubled to start, but stayed where he was when Phils reliever Justin De Fratus mishandled a Ramos dribbler. Pinch-hitter Scott Hairston's fly off Jake Diekman moved Rendon to third and he scored when Diekman threw wild to first on a Denard Span grounder.
Gonzalez hasn't lost in his last eight outings, since a 6-2 setback against Baltimore on May 27 ... Lee hadn't lost since May 1 at Cleveland, and the four homers he surrendered were the most since he served up four to Milwaukee on July 24, 2012 ... Before his homer, Zimmerman was 4-for-23 against Lee ... Prior to the game, the Phillies announced that first baseman Ryan Howard underwent successful surgery on the meniscus in his left knee, and will miss 6-to-8 weeks recovering.