Washington, led by new leadoff hitter Bryce Harper, pounded the Pirates again Wednesday night, this time 9-3.
Harper went 3-for-5 with three RBIs. He started the bottom of the first inning with a second-deck shot to right-center off Ivan Nova for his 10th homer of the season. It was his second homer in two nights and the first leadoff blast of his career.
"We'll let it ride and see what happens," Nationals manager Dave Martinez said of the new lineup after the game. "The boys are doing well. Like I said, (Harper's) getting pitched to a little bit now and he's swinging the bat really well."
Matt Adams clubbed his third homer in two games for Washington (15-16).
"The big thing is getting Bryce pitches to hit," Adams said. "You look at our lineup, no matter what it is, one through nine is pretty tough. Whatever lineup we throw out there we can put runs on the board."
Harper doubled and scored in the third, drove in a run with a fielder's choice in the fourth and singled home a run in the fifth before grounding out in the seventh.
Stephen Strasburg (3-3) allowed three runs (two earned) and seven hits in seven innings.
Pittsburgh (17-14) came into Washington riding a five-game winning streak, but has lost the first three games of the series, the last two by a combined score of 21-7 as Washington's bats have come alive.
"I thought as a team we went out there and did our job, just like yesterday," Harper said. "Everybody swung the bat well, one through nine everybody contributed and Stras threw the ball great."
Nova (2-2) allowed eight runs (five earned) on 11 hits over 4 2/3 innings. He struck out five and walked two.
"It's not just about pitching," Pirates manager Clint Hurdle said. "We play better defense, we do something on offense earlier, it can change the landscape of the game as well."
Pittsburgh will send right-hander Trevor Williams to the mound against Jeremy Hellickson in the finale.
Williams (4-1, 2.29 ERA) allowed two runs over six innings in a victory over St. Louis in his last start. He has allowed only one home run on the season. It came at Wrigley Field.
"Keeping people off home plate. I'm serious. That's what he's done the best," Hurdle said of Williams' success. "There's been baserunners. He hasn't given in ... his pitch efficiency's been higher than we've seen in the past when he's pitched well. But the mix of pitches, he's been stubborn, he's been steadfast and he's been gritty."
Williams is 2-0 with a 1.50 ERA in three road starts this season.
In his only previous work against Washington, he allowed a run in two-thirds of an inning of relief.
Last time out, Hellickson (0-0, 4.11) allowed two runs on five hits and a walk in 5 1/3 innings against the Arizona Diamondbacks. Both runs came on solo homers by David Peralta.
Hellickson is 3-1 with a 2.86 ERA and a .187 opponents' batting average in five starts against Pittsburgh.
The Pirates' Gregory Polanco is 4-for-11 with a home run against Hellickson, while Francisco Cervelli is 0-for-9.