PHILADELPHIA -- Throughout the last few seasons, the Philadelphia Phillies have found it hard enough to beat Washington Nationals pitcher Stephen Strasburg when he's on his game.

Helping himself at the plate only makes the task against Strasburg more difficult.

Strasburg tossed 5 2/3 innings of shutout baseball, blasted a second-inning home run and helped lead the Nationals to a 4-2 win over the Phillies on Friday night at Citizens Bank Park.

Strasburg (3-1) had his night cut short thanks to poor command. He threw 119 pitches, walked four batters -- one intentionally -- and struck out five while allowing just five hits. In the process, he lowered his career ERA against the Phillies to 2.37. It was the first time he failed to go seven innings this year.

"I want to be out there," Strasburg said. "I'm going to go as hard as I can as long as I can. ... They battled."

The Nationals (20-9) have won three in a row and four of five. Philadelphia (12-16) dropped its fourth straight and sixth in its last seven games.

With his team already up 1-0, Strasburg, after fouling off three fastballs in the at-bat, blasted a 1-2 fastball for a 404-foot home run to left-center in the second inning off Phillies starter Nick Pivetta (0-2). It was Strasburg's second career home run -- first since 2012 -- and his first base hit of 2017.

"I had no business swinging at that pitch," Strasburg said. "I don't know how I connected on it."

Pivetta lasted five innings and was tagged for four runs and nine hits. He struck out six and walked none, but allowed three home runs.

Ryan Zimmerman and Anthony Rendon hit back-to-back homers off Pivetta to up the lead to 4-0 in the fifth, giving the Nationals much-needed insurance.

"I didn't like those two runs," Pivetta said. "That was a big turning point for the game."

Washington's bullpen, which has struggled to both pitch effectively and stay healthy, was tasked with the last 10 outs without closer Shawn Kelley (back), who was placed on the disabled list Friday.

The Phillies cut into the lead on a pair of RBI doubles from Odubel Herrera and Tommy Joseph in the seventh off Washington reliever Blake Treinen.

But Enny Romero gave the Nationals four outs (three strikeouts) to get through the eighth inning and Matt Albers notched his first save of 2017.

"These guys are giving me all they've got," Nationals manager Dusty Baker said of the bullpen. "We've been mixing and matching and doing what we have to do."

The Nationals made Pivetta's first start at home a rough one right off the bat. They forced the righty to throw 29 pitches in the first inning. With the bases loaded and one out, Rendon knocked in Jayson Werth with an RBI single to open the scoring. Pivetta got out of the inning without further damage, however.

While Strasburg was on cruise control through three innings, the Phillies let an opportunity go to waste in the bottom of the fourth. With Maikel Franco on first base and one away, Michael Saunders sent a Strasburg pitch all the way to the wall in right field, where Washington center fielder Michael Taylor failed to make a catch. It fell in for a double, but Franco didn't get past third because he was held up thinking the ball might be caught.

With two men in scoring position and just one out, Strasburg buckled down. First, he fanned catcher Cameron Rupp with a fastball. Then, after intentionally walking shortstop Freddy Galvis to get to Pivetta, Strasburg whipped a 95-mph fastball by Pivetta to get out of the jam.

"We made him work," Phillies manager Pete Mackanin said. "He threw a lot of pitches. The bottom line is we got to score. We didn't score."

NOTES: Prior to the start of the game Friday, the Nationals placed RHP Shawn Kelley on the 10-day disabled list with a lower back strain and recalled LHP Matt Grace from Triple-A Syracuse. ... The Phillies on Friday recalled RHP Jake Thompson to provide some length to their bullpen -- one that entered Friday having given up a league-high 21 homers -- and sent IF/OF Ty Kelly to Triple-A Lehigh Valley. ... Washington SS Trea Turner extended his on-base streak to 15 games when he was hit by a pitch in the fourth inning. ... RHP A.J. Cole makes his 2017 debut Saturday for the Nationals against RHP Vince Velasquez (2-2, 5.47 ERA) of the Phillies.