PHILADELPHIA -- The Washington Nationals are just where they want to be at the All-Star break: atop the NL East.
"If you told us earlier we'd be in this spot at this time, everybody would feel good," Werth said. "We're healthy now and we kept our heads above water. I like where we are."
The Nationals (51-42) won the last two games of the series and entered the break in a virtual tie with Atlanta (52-43) for the NL East lead.
"We're right in the thick of the division," Nationals manager Matt Williams said. "This is a great way to finish up the first half. It's momentum for us."
The Phillies finished a forgettable first half in familiar fashion, producing little offense against Roark and Ross Detwiler. Philadelphia scored two unearned runs off Aaron Barrett in the ninth to end with three runs or fewer for the 49th time this season.
"We didn't get anything going on the offensive side of things," manager Ryne Sandberg said.
The Phillies dropped to 8-41 overall and 2-29 in their last 31 games when failing to score four runs. Cody Asche had two doubles and an RBI for Philadelphia, which fell 10 games behind Washington.
It was the second straight defeat for Philadelphia after a five-game winning streak in which the Phillies averaged 6.2 runs. They had no answers for Roark (8-6), who allowed a run and four hits. He struck out six and walked none.
"I pitched with confidence," Roark said. "I didn't nibble."
Kyle Kendrick (4-9) continued his pattern of struggling badly in the first inning and then pitching well.
Werth followed consecutive singles by Denard Span and Rendon to lead off the game with an opposite-field shot that quickly made it 3-0. But Kendrick settled down and retired 14 straight batters until Roark's two-out single in the fifth.
The Phillies couldn't recover.
"It was a tough tone set for us early on in the game, and we didn't bounce back from that," Sandberg said.
Kendrick ran into trouble in the sixth when the Nationals scored four runs off him and left-handed reliever Mario Hollands. Kendrick allowed Rendon's single to start the frame and then hit Werth to put runners on first and second before getting Adam LaRoche to fly out.
Zimmerman's one-out sacrifice fly scored Rendon and chased Kendrick. Hollands then surrendered three straight hits, including Desmond's two-run double and Jose Lobaton's RBI single, that broke open the game.
Kendrick left after allowing five runs on five hits with five strikeouts and no walks in 5 2/3 innings. The focus was on his first-inning struggles.
"It's just quality pitches," Kendrick said. "I just have to make pitches in that first inning. That's what it comes down to."
The Phillies got a run back on Ryan Howard's groundout in the sixth.
Werth remained hot in July, upping his average this month to .375 (15-for-40) with six homers and 19 RBIs.
LaRoche went 0-for-5 with a strikeout to drop his average in July to .122 (5-for-41). He was the only Washington starter not to get a hit on Sunday.
Nationals reliever Tyler Clippard was selected to the All-Star game by NL manager Mike Matheny, replacing Braves starter Julio Teheran. Clippard will be the only Washington representative after starter Jordan Zimmermann had to bow out on Saturday because of a right biceps strain. Clippard, who earned the win for the NL in his only other All-Star appearance in 2011, is 6-2 with a 2.03 ERA in 40 innings. ... Desmond, who led major league shortstops in RBIs entering Sunday, raised his total to 57. ... Phillies left-hander Cliff Lee, on the DL since May 19 with a left elbow strain, will return to the mound on July 21 against San Francisco. ... Chase Utley will represent the Phillies at the All-Star game, making his sixth appearance. The only NL second basemen to make more All-Star starts than Utley are Hall of Famers Joe Morgan (seven) and Sandberg (nine).