PHILADELPHIA -- A mechanical adjustment in between starts helped A.J. Burnett out of a funk.
"I just noticed something with my delivery, or the leg kick," Burnett said. "I just noticed something wasn't right. I was like, `That's not me out there. Who is that?' It's the first time I felt like me in a long time."
Domonic Brown had two hits and an RBI for Philadelphia, which won for the fourth time in five games.
Burnett (7-14) won for the first time since the All-Star break, allowing one run on three hits with just one walk. The right-hander entered leading the majors in walks with 76.
"I wish I could have found that little glitch about a month, two months ago," Burnett said. "Unfortunately it took a long time, but better late than never."
Tanner Roark (12-8) gave up two runs on five hits in six innings and lost for just the second time in his last nine starts. Roark has a 2.25 ERA over that stretch.
"I felt good, I felt confident," Roark said. "I had command on both sides of the plate. My offspeed was good."
Burnett retired the first eight batters before Roark's two-out single in the third. It was just the pitcher's sixth hit in 60 at-bats this season.
The Nationals didn't get another hit until Rendon's one-out homer to left in the sixth that pulled them within 2-1. It was the third homer 15 at-bats for Rendon off Burnett.
"If he hits it good, the ball's going to carry," Nationals manager Matt Williams said. "He's been a very pleasant surprise."
Burnett had been 0-6 with a 7.41 ERA in seven starts since the All-Star break prior to Monday. But he was stellar against Washington, setting a season-high in strikeouts while finishing in double-digits for the 35th time in his career.
"The difference was more strikes on the board early on in the at-bats," Phillies manager Ryne Sandberg said.
The Phillies took a 1-0 lead in the fourth on Brown's RBI single and went up 2-0 on Asche's leadoff homer to deep right in the fifth.
"It was a changeup but it didn't change," Roark said. "It was right down the middle, thigh high, and he got me."
After Washington closed within a run, Ruiz cleared the wall in left off left-hander Jerry Blevins to push Philadelphia's advantage to 3-1.
Ramos homered to right with two outs in the ninth off Jonathan Papelbon, who earned his 32nd save in 34 opportunities.
Chase Utley went 0-for-4, extending his slump to 3-for-29.
Nationals: Second baseman Asdrubal Cabrera was out of the starting lineup after injuring his rib in Sunday's 14-6 win over San Francisco. Manager Matt Williams said prior to the game that Cabrera is day-to-day. Cabrera pinch-hit in the ninth inning and singled.
Phillies: OF John Mayberry Jr. (wrist) played in his fifth rehab game with Triple-A Lehigh Valley on Monday night. Mayberry entered 4-for-14 with a homer and three RBIs in four games there.
Nationals: LHP Gio Gonzalez (6-9, 3.83) takes the mound for Washington at 7:05 Tuesday. He pitched seven shutout innings but got a no-decision in the Nationals' 1-0 win over Arizona Thursday. Gonzalez has received two runs of support over 33 1/3 innings in his last six starts.
Phillies: LHP Cole Hamels (7-6, 2.53) got rare run support in his last outing when he snapped string of seven straight starts with at least seven innings in a 4-3 win over Seattle Wednesday. Hamels is 15-7 with a 2.54 ERA in 30 careers starts against Washington.
The Nationals challenged second-base umpire Gary Cederstrom's safe call on Brown's would-be double leading off the seventh inning, and the call was overturned by replay review after an estimated delay of 2:02.
MOVING UP SAVES LIST
Papelbon earned his 318th career save, tying Rick Aguilera for 18th all-time in saves.