The Nationals dugout got to dancing after right fielder Adam Eaton smashed a two-run homer in the fifth inning of Wednesday’s win over the Cincinnati Reds. (Katherine Frey/The Washington Post)

The line drive landed foul, by no more than a few feet, and so a loud cheer dissolved into a heavy sigh at Nationals Park on Wednesday afternoon.

It could have been Stephen Strasburg’s latest big moment at the plate — if not for those few feet — but he now had to walk back to the batter’s box and start again. He worked a full count against Cincinnati Reds starter Trevor Bauer. The energy rose back up with every pitch. Then Strasburg stuck his bat out and lofted a single that splashed into the right field grass. Bauer looked agitated. A tiebreaking run came in. Then the loud cheers wouldn’t stop.

What unfolded next was the best offensive inning of the Washington Nationals’ season. And what came after that was a 17-7 win, completing a three-game sweep of the Reds.

The Nationals put up 10 runs in the fifth, starting with Strasburg’s RBI single and ending with Kurt Suzuki’s three-run home run. Adam Eaton and Anthony Rendon hit back-to-back homers during the rally. Washington scored six more in the sixth, with its first eight batters reaching base, and that helped the Nationals pass their previous season high of 15 runs. Every position player in the order had scored twice by the end of that inning. The Nationals, in turn, are 10 games over .500 for the first time since June 13, 2018.

“Hitting is contagious. They say it all the time,” Suzuki said. “When you get guys to swing the bats, get the ball rolling, get guys on base, you know, things happen. One guy hits, and it seems like everybody keeps hitting.”

With Strasburg and Bauer pitching and shadows covering the infield by late afternoon, each side started with a slim margin for error. Both right-handers cruised through the first two innings. Bauer hit a bump in the third, giving up a run on a sacrifice fly. Strasburg hit his bump in the fourth thanks to three wild pitches, and he had to swallow Eugenio Suárez scoring on a strikeout. He came into the game with a 3.72 ERA and now has a National League-leading 15 wins. Bauer, traded from Cleveland to Cincinnati at the trade deadline, a top arm, was the right match for a pitchers’ duel.

And so it was fitting Strasburg was the one to disrupt it.

“I guess you lower your expectations enough and you just try and grind,” Strasburg said of his plate approach. “You just try and make it as hard as possible on the pitcher.”

The former Silver Slugger award winner has spent the summer padding his résumé. He crushed a three-run homer in Atlanta on July 18, added two singles and finished the game with a career-high five RBI. He singled in his first at-bat of his next game, giving him a hit in four consecutive plate appearances, and added another in his next game after that. Then Strasburg slumped — or acted like a normal pitcher — by going hitless in his first six plate appearances of August. Then he kick-started a landslide.

Asdrúbal Cabrera led off the fifth with a single, Suzuki bounced into a fielder’s choice, and Victor Robles doubled to put runners on second and third. Strasburg’s initial contact, that liner to right, got a rise out of a half-filled stadium. Bauer worked him tougher after that, mixing in his biting slider, making sure to stay away from the middle of the plate. He threw a 3-2 cutter way outside, and it could have been ball four, but instead Strasburg check-swung it into right.

Suzuki scored. Robles raced into third. Strasburg clapped his hands once at first, his job finished, and that’s when everyone got involved. Trea Turner dribbled an RBI single up the middle. Eaton’s eighth homer of the season landed just past the 402-feet sign in center. Rendon’s 26th, a career high, nearly fell in the same spot. Juan Soto singled, Matt Adams walked, Bauer exited while shaking his head, Cabrera doubled, and Suzuki provided the loud exclamation point.

“They got a hit on my change-up, slider, four-seam, two-seam. I don’t know,” Bauer said after using about 350 words to recap every at-bat of the fifth. “It’s kind of confusing when you’re there. I don’t know what else short of throwing an eephus pitch or changing an arm angle. You’re just trying to guess.”

Suzuki’s three-run blast made it so every player in the lineup — from Turner down to Strasburg — scored in the inning. Suzuki crossed the plate twice. Nine straight batters reached with a hit or walk. Bauer didn’t retire the last seven he faced. His final line included a career-high nine runs, eight of them coming in a blink, and that allowed Washington to coast toward a day off.

There were still four innings to get through. Strasburg (15-5) gave up three more runs, completed 5⅔ and exited at 110 pitches. The Nationals restored their lopsided lead, and then some, in the next half. But they had done enough damage in the fifth to grab control of an otherwise lazy afternoon. And their first real signs of life came from Strasburg’s bat.