Washington, DC (SportsNetwork.com) - Scott Hairston's walk-off sacrifice fly in the 11th inning gave the Washington Nationals a 6-5 victory and a three- game sweep over the Pittsburgh Pirates in a back-and-forth affair on Sunday.
Brandon Cumpton (3-4) gave up a leadoff double to Jayson Werth off the left- field wall to start the bottom of the 11th inning. Denard Span's groundout moved Werth to third before Hairston's pinch-hit sac fly to deep left scored the game-winning run.
"It wasn't the prettiest win, but it didn't have to be. The guys fought hard," Nationals manager Matt Williams said. "We have a lot of tenacity."
Asdrubal Cabrera and Ian Desmond each drove in a run and Werth scored twice for the Nationals, who walked off for the second night in a row and won their season-high sixth straight game.
Ross Detwiler (2-2) earned the win after allowing just one hit over the final two innings. Starter Doug Fister did not factor in the decision, but was solid, giving up just two unearned runs on five hits with five strikeouts over seven innings.
Gregory Polanco hit a two-run double in the ninth and Russell Martin brought in a run for Pittsburgh, which has lost five consecutive games for the first time since 2012.
"You embrace it when it's good and you embrace it when it's hard," said Pirates manager Clint Hurdle. "We are going to show up and we are going to play. We will keep pushing."
Pittsburgh went ahead 2-0 in the sixth. Polanco got aboard to start the frame on Desmond's fielding error and Josh Harrison's base hit placed runners on the corners. Neil Walker's hit to the mound was corralled by Fister and thrown to third baseman Anthony Rendon, but Polanco scored after Nationals catcher Wilson Ramos couldn't handle the throw at the plate.
Martin followed with an RBI single and Pedro Alvarez's base hit loaded the bases, but Fister escaped the jam by retiring the next three batters.
The Nationals got a run back in the home half. Rendon singled with two outs, moved to second on Adam LaRoche's walk and scored on Desmond's single to center.
Washington loaded the bases in the seventh off Pirates starter Edinson Volquez. After Jared Hughes took the mound, Cabrera reached on a failed force attempt at home as Ike Davis' throw from first to home was off the mark, allowing two runs to score. Denard Span then scored after Rendon's dribbler to third was picked up by Alvarez and his throw sailed over Martin at home.
With the Nationals on top 4-2, Rafael Soriano hit Starling Marte with a pitch to start the ninth. He then gave up a single to Travis Snider to place men at first and third and Marte came home on a wild pitch to get the Pirates within one.
Gaby Sanchez grounded into a force out at third for the first out, but Polanco crushed a double off the right-field wall, bringing in two runs for a 5-4 lead.
Mark Melancon came on to pitch the ninth for the Pirates. Werth worked a one- out walk, moved to third on Span's single to right and scored on Cabrera's base hit to tie the game and send it into extras.
Both teams had 10 hits and two errors ... Washington won the season series, 4-3. It is the first time the Nationals have won a 7-game season series after losing the first three games ... Volquez gave up four runs -- one earned with two walks and five strikeouts over 6 1/3 innings ... Fister didn't allow a hit until Alvarez's single opened the fifth ... Snider extended his hitting streak to eight games ... The Nationals are 59-7 when scoring four runs or more ... Pittsburgh went 4-for-14 with runners in scoring position.