Bryce Harper rounds third base en route to scoring the winning run in the Nationals’ extra-innings victory over the Phillies on Friday. (Jonathan Newton/The Washington Post)

There will be days in this long season when the Washington Nationals will not mash their way to victory. It may not happen often for a lineup as deep as theirs, but it will happen, and when it does, the onus shifts to the club’s other facets — to the starting pitcher, the bullpen and the defense — to provide the club with a win. Friday was one of those days.

Stephen Strasburg continued the Nationals starters’ run of dominance and held the Philadelphia Phillies to two runs over seven innings . A defense that had made nine errors in Washington’s first nine games — a number the Nationals didn’t reach until Game 27 last season — committed none Friday. And the bullpen, the scrutinized one with a 6.75 ERA in 29⅓ innings, didn’t concede a run in three innings, holding on long enough for Daniel Murphy to double home Bryce Harper in a 3-2, 10-inning walk-off victory at Nationals Park.

Murphy’s double was a line drive down the left field line off Jeanmar Gomez, the Phillies’ closer until the Nationals (6-4) scored three runs against him Sunday in Philadelphia. Harper had singled to lead off the frame, and third base coach Bob Henley, never hesitant to gamble, waved him home, with Harper’s helmet flying off and bouncing off the back of his left foot as he rounded the bag. Harper completed the 270-foot scamper with a smooth headfirst slide. Jayson Werth was there for a hug.

“I was just trying to score,” Harper said. “I didn’t want to play extras.”

The double was Murphy’s second hit of the game. He has a hit in all 10 games this season and has multiple hits in seven of them. He leads the majors in hits with 20.

“He might [be doing] better than he did last year, which is hard to believe,” Nationals reliever Shawn Kelley said. “That guy is special. I want to be like him when I get older.”

Added Nationals Manager Dusty Baker: “You don’t take him for granted. You realize this guy’s one of the best hitters in the world.”

Anthony Rendon had two hits, including the game-tying RBI double in the seventh, but the Nationals’ offense was suppressed for most of the day for the second straight game. And for the second time in less than week, they had trouble solving Aaron Nola. After he held Washington to three runs across six innings in Philadelphia last Saturday, the 23-year-old Nola was even better a couple hundred miles down Interstate 95 on Friday. The right-hander surrendered one run on six hits with six strikeouts over five innings and needed 90 pitches to do it.

The weather, sunny and 70 degrees, was glorious for the oddly timed 4:05 p.m. first pitch from Strasburg, who plowed through the first five Phillies from the stretch. Then he encountered Tommy Joseph, who walloped a 1-0 fastball just over a leaping Adam Eaton — and the part of the wall in center field with “402 feet” stamped on it.

The Phillies (3-7) tacked on another run in the fifth inning. The run, like the Phillies’ first, was created with two outs, which prolonged an early-season trend: Six of the seven runs Strasburg has yielded this season have come with two outs. But that was all the Phillies would generate off Strasburg. From there, home plate umpire Dan Bellino caused more strife for Strasburg then anyone in Philadelphia’s lineup.

A couple of Nationals, including Wilmer Difo and Harper, already were disgruntled with Bellino’s work when Strasburg expressed some frustration in the sixth inning. First, Strasburg thought he had strike three on Odubel Herrera twice, the second time dropping to a knee to accentuate his disbelief as Bellino called the pitch, a 96-mph fastball over the plate at the bottom of the strike zone, ball three. Ball four followed.

Strasburg got Maikel Franco to ground into a double play before another Bellino decision irritated him. This bout of incredulity spawned from Bellino calling a 2-2 change-up to Michael Saunders, which appeared in the strike zone, ball three. Saunders stroked the next pitch for a single. Strasburg again recovered after pitching coach Mike Maddux visited the mound, inducing a groundout to end the inning, but he appeared to have words for Bellino as he walked back to the dugout with his pitch count reading 98.

“To be honest, it kind of got in my head a little bit,” Strasburg said. “But [I] just kept telling myself, ‘All right, I’m going to make that pitch again.’ That’s all I can do.”

The Nationals scored their first run in the second inning on a Matt Wieters RBI single, and the bats finally offered Strasburg more support in the seventh, when Chris Heisey, pinch-hitting for Strasburg, walked and came around to score on Rendon’s two-out double. It was the scuffling Rendon’s first extra-base hit of the season in his 36th plate appearance.

Strasburg returned for the seventh, tossing another 13 pitches to retire the Phillies in order and complete his day. The 111 pitches were the most he has thrown in a game since May 19. He threw more than 111 just one other time in his 24 starts last season.

Koda Glover was assigned the eighth inning and needed 12 pitches to dismiss the Phillies in order. Blake Treinen’s ninth inning was not as easy on the stomach for the hearty crowd, but the sinkerballer coaxed a groundball from Cameron Rupp for an inning-ending 4-3 double play. Kelley then pitched a perfect 10th, setting the stage for Murphy to walk it off on his bobblehead day.

“It seemed like the stars aligned for that one,” Strasburg said.