WASHINGTON -- Call this the Stephen Strasburg sweep.
The 21-year-old rookie started it with a phenomenal debut, and his Washington Nationals teammates fed off the energy to become the last team in the majors to sweep a series this season, capping it off Thursday night with a 4-2 win over the Pittsburgh Pirates.
"This last homestand was pretty good with Stephen coming in," said Michael Morse, whose three hits included his first homer of the season. "It kind of gave us a little jump, and we're feeling good."
Adam Dunn homered for the third straight game, Josh Willingham also went deep, and Livan Hernandez (5-3) allowed two runs over six innings for his first win in more than a month despite a respectable string of starts.
And, lest it be lost in the Strasburg hype, it's worth noting that the Nationals bullpen pitched shutout ball the entire series, allowing nary a run over 10 1/3 innings. Even with regular closer Matt Capps getting the night off, Tyler Clippard was able to send the side down in order in the ninth Thursday for his first career save.
"It seems like every day a new guy out of our 'pen kind of steps up," Clippard said. "And I think that says a lot to the other teams around the league as far as what we can throw at teams."
After Strasburg's debut drew a sellout crowd of 40,315, the next two nights were tame events by comparison -- drawing 40,637 for both games combined. Still, all three count equally as wins for a Nationals team that has pulled within a game of .500.
Zach Duke (3-7) pitched better after two subpar outings but suffered again from a lack of run support for the Pirates, who have lost five straight.
Duke allowed three runs -- two earned -- over five innings and scored Pittsburgh's first run after leading off the sixth with a double.
"I thought we swung the bats OK. We just can't create runs. That's been our problem," manager John Russell said. "Until we start scoring more runs, every pitch means something. The pitcher's backs are against the wall too often. We need to start getting some offense going."
Dunn gave the Nationals the lead when he hit a curveball into the middle deck in right field in the fourth inning for his 13th home run of the season. Two batters later, Willingham got his 12th homer when he took Duke's full-count fastball to left-center to make the score 2-0.
The Nationals added an unearned run in the fifth. Dunn singled, was balked to second, then scored on third baseman Andy LaRoche's errant throw to first on a grounder by Ryan Zimmerman.
The Pirates got two in the sixth, an inning that began with back-to-back doubles by Duke and Jose Tabata. Speedy outfielder Tabata, who made his major league debut Wednesday, is 3 for 8 in his first two games.
The Nationals loaded the bases with none out in the sixth on a walk and two singles, but Evan Meek -- whose ERA sits at 0.76 -- got pinch-hitter Willie Harris to line into a double play and retired Cristian Guzman on a groundout.
Washington also wasted Ian Desmond's leadoff double in the seventh, stranding him at third, but Morse's homer gave the Nationals an insurance run in the eighth.
Morse is hitting .500 (9 for 18) since coming off the disabled list last month, but he's having to settle for limited playing time as the Nationals settle into a regular starting outfield.
"I could pretty much see the situation," Morse said. "That's my role on the team, and I'm happy with it and I'm going to do the best that I can."
Ryan Doumit returned for the Pirates after missing three games with concussion-like symptoms from taking a foul tip off his facemask, starting at first base for the first time since 2007. Manager John Russell said Doumit might resume catching duties on Sunday. ... The Nationals went 4-2 over six games at Nationals Park, their fourth straight winning homestand.