Ian Desmond belted his first career grand slam in the 11th inning to boost the Washington Nationals to a 6-2 win over the Philadelphia Phillies in the conclusion of a three-game series.
Jayson Werth drove in the other two runs for the Nationals, including the tying single in the ninth inning against Jonathan Papelbon.
Washington snapped a three-game skid and broke Philadelphia's six-game winning streak at Citizens Bank Park.
Michael Young belted a two-run homer for the Phillies, who had just four hits.
Ryan Zimmerman doubled to left-center off Michael Stutes (2-1) with one out in the 11th. Adam LaRoche was intentionally walked and Werth drew a free pass.
Stutes had Desmond down 0-2 but could not put him away. On a 1-2 pitch that was seemingly down the middle, home plate umpire Alfonso Marquez squeezed the zone and called a ball. Phillies manager Charlie Manuel barked from the dugout, but on the next pitch Desmond, who came into the game hitting .410 for his career with the bases full, homered to left-center field.
"He came back with a slider. The ball was down and Desmond hit it out," Manuel said.
Gio Gonzalez tied a career-high with 11 strikeouts over seven innings for the Nationals. Drew Storen (2-1) fanned a pair in the 10th to get the win.
Kyle Kendrick allowed two hits, a run and a walk, while fanning six over 7 2/3 innings in the start for the Phillies.
Ben Revere led off the bottom of the first with a single. Young, who doubled three times on Tuesday, upped his RBI total to 1,001 for his career with his homer to left field.
After the first two batters got hits, the next one for Philadelphia didn't come until the 10th when Carlos Ruiz singled up the middle with two outs. Pinch-hitter Michael Martinez then flied out to left.
After Young's homer, Gonzalez allowed only two more runners, on walks to Jimmy Rollins and Kendrick in the fourth and sixth innings, respectively.
Zimmerman walked in the seventh inning, and he scored on Werth's two-out single to right field.
Denard Span started the ninth inning by hitting a ball to the right side of the infield. Second baseman Freddy Galvis, a defensive replacement, threw low to Papelbon covering first, and the closer couldn't make the grab.
Papelbon retired the next two batters, but LaRoche walked and Werth grounded a base hit to left field. The throw to the plate was cut off as Span came home as Papelbon suffered his second blown save of the series.
The Phillies put the potential winning run at second in the bottom of the ninth, but Domonic Brown, the hero of Monday's last at-bat win, hit a soft liner to shortstop for the final out.