Bryce Harper, who drew four walks on 20 pitches, comes around to score in the fifth inning of the Nationals’ 15-1 win over Atlanta on Thursday. (Katherine Frey/The Washington Post)

For one night at least, there was no need for blame, no reason for second-guessing, no decisive swing or pitch to yield regret. For one night, there was no stress, no doubt, no frustration. For one night, things came easily for the Washington Nationals.

The Nationals battered the Atlanta Braves, 15-1, on Thursday night, opening a seven-game homestand with a win, picking up a half game on the idle New York Mets, who lead the National League East by six games. They did not have to watch the scoreboard and hope for help. They did not need much help at all against the Braves, who entered Thursday’s game having lost 15 of 16.

Games like these, against struggling teams and non-contenders, are the ones the Nationals must win. They play the weak NL East division for much of September, but they have not dominated the league’s meekest teams as the resumes on their roster suggest they should. Washington is 44-36 against sub-.500 teams. The Mets are 54-26.

The Nationals dominated from start to finish, winning by the widest margin of victory in Nationals history. When first baseman Ryan Zimmerman walked to the plate with two outs in the first inning, the crowd stood and cheered, grateful for his prolific series in St. Louis, applauding his 200th career home run, hit while the team was away. No one had a chance to sit before he hit a double off the right-center field wall, the first of 18 Nationals hits.

Zimmerman is 17 for 42 (.404) with five doubles, seven home runs, two walks and 23 RBI over his past 11 games. He went 3 for 3 with four RBI on Thursday. He played five innings. In the sixth, Nationals Manager Matt Williams pulled most of his regulars.

“I just think coming back [from St. Louis], being back at 4:30 this morning, not being in bed until 5, 6 o’clock in the morning, we definitely needed that tonight,” center fielder Bryce Harper said. “Get some of the starters out of there and get us a breather.”

By the third inning, every Nationals starter had reached base, including pitcher Jordan Zimmermann. By then, Zimmerman had three RBI, Harper had walked three times and three Nationals had scored two runs each. Zimmermann was wild early, hurt by a tight strike zone by home plate umpire Clint Fagan. It did not matter much in the end. As the lead grew, he attacked more, lasting six innings in which he allowed just one run, two hits and walked four, tying his season high.

“I just had to start throwing the ball over the middle a little more. Couldn’t nibble on the corner,” Zimmermann said. “Then when they got me those runs, I was in attack mode the rest of the game.”

The Nationals pummeled Braves starter Matt Wisler, who got just five outs while allowing seven runs on five hits. The Braves used eight pitchers. The Nationals scored runs in all but two innings.

“To come out and get a big lead and hold on to it and kind of coast to an easy win, those are always welcome,” left fielder Clint Robinson said.

Anthony Rendon had a hit and scored three times, extending his hitting streak to 12 games. Wilson Ramos doubled and singled, extending his to 11. Yunel Escobar went 3 for 4 with a walk and three runs batted in. Robinson finished 2 for 3 with four RBI.

Harper walked four times in four plate appearances and scored four times, making him the fourth player in baseball history to score four runs in a game in which he had no official at-bats. He saw 20 pitches and did not swing at any of them, the second-most pitches without a swing for any batter in one game in the past 10 seasons.

Tyler Moore pinch-hit for Jayson Werth in the sixth inning. He was activated from the disabled list before the game and had missed 14 games with a sprained ankle. He doubled. Danny Espinosa pinch-hit for Ryan Zimmerman in the sixth. He singled, then hit a solo home run in the eighth.

Trea Turner, 0 for 9 in his major league career entering Thursday night’s game, came in to play shortstop in the seventh. He beat out a chopper to second base when the throw bounced away from Braves first baseman Freddie Freeman. The official scorer awarded him a single, his first major league hit. The Nationals scored the third-most runs they have all season, accomplishing the feat with just one home run, Espinosa’s solo shot.

“Outside the guys that are the everyday starters having success, the guys who got in the game tonight had some, too, which is real good,” Williams said.

Throughout much of the onslaught, Williams leaned over, hands on his knees, sometimes leaning on the railing, face steady as ever. After all, his Nationals have another game Friday. It probably will not be so easy. Few have been.