Bryce Harper tripled, singled and drove in two runs for the Nationals, who won their third straight game and beat the Phillies for the sixth straight time in Philadelphia - something that never had been done in the franchise's 43-year history. Washington has defeated Philadelphia in four of the five meetings this season and 13 of the last 16 overall.
Erik Kratz homered for Philadelphia, which lost its season-worst fourth straight game while struggling once again with runners in scoring position. The Phillies have scored three runs in their last three games and are 5 for their last 38 with runners in scoring position. .
Zimmermann (3-4) earned his first win in five career starts against Philadelphia, surrendering one run and seven hits in six innings. He entered 0-3 with a 6.00 ERA against the Phillies.
Tyler Clippard, who was taking the place of demoted closer Henry Rodriguez, pitched a scoreless ninth to earn his first save in two chances. Manager Davey Johnson told reporters before the game that Rodriguez no longer would be the team's closer after converting 9 of 12 save opportunities this season. Johnson said he would go with a closer-by-committee approach.
Roy Halladay (4-4) continued his indifferent season with his second-worst start of the season, going six innings and allowing five runs and nine hits with six strikeouts and one walk.
It was especially surprising against the Nationals, a franchise Halladay has dominated with an 11-1 record and 2.28 ERA in 16 career starts. His last loss to the Washington franchise came on June 28, 2002 as a member of the Toronto Blue Jays against the then-Montreal Expos.
Halladay's only worse start this season was May 2 at Atlanta when he gave up eight runs and 12 hits in 5 1-3 innings. After winning his first three decisions, Halladay is 1-4 with a 4.75 ERA in his last seven starts.
The Phillies took a 1-0 lead in the second inning on Hector Luna's grounds-rule double to center before the Nationals scored four runs in the third.
After consecutive singles to open the inning by Zimmerann and Steve Lomardozzi, Harper tripled to deep right-center to give the Nationals a 2-1 lead. Harper scored on Adam LaRoche's sacrifice fly, and Desmond homered to left to put Washington up 4-1.
It was Desmond's eighth homer of the season and fourth in his last seven games.
Philadelphia catcher Carlos Ruiz was ejected in the frame when he argued a called ball on the second pitch to Danny Espinosa, the final batter of the inning.
The Nationals tacked on a run in the fourth when Ankiel drove the first pitch he saw from Halladay over the fence in center.
As they have during the losing streak, the Phillies continued to struggle with runners in scoring position. The most glaring example Tuesday came in the third inning when Placido Polanco singled and Shane Victorino doubled to put runners on second and third with one out. But Zimmermann got Hunter Pence to strike out and Brian Schneider to fly out to center.
Philadelphia left two runners on base in the second through fifth innings.
The Phillies did get a run in the eighth on pinch-hitter Kratz's first career homer, a drive to center off reliever Tom Gorzelanny. Kratz was called up from Triple-A Lehigh Valley before the game after Jimmy Rollins was placed on the three-day Paternity List following the birth of his daughter on Sunday night.
Notes: Washington's Ryan Zimmerman was removed from the lineup just before the game after initially being slated to bat third and play third base. He was replaced by Chad Tracy. .. Phillies RHP Vance Worley will not need Tommy John surgery on his elbow after consulting with Dr. James Andrews. Worley has right elbow inflammation and indicated he has a bone chip and may need surgery after the season. . The crowd of 45,569 was the Phillies' 227th straight sellout and 243rd counting postseason play. .. Philadelphia LHP Cole Hamels (6-1, 2.48) is scheduled to face Washington RHP Edwin Jackson (1-1, 3.31) in the series finale Wednesday night. Hamels sparked a firestorm of controversy in his last start against Washington on May 6 when he intentionally hit Harper, an incident that earned Hamels a five-game suspension.