Nationals first baseman Ryan Zimmerman, left, is congratulated by second baseman Daniel Murphy after a solo home run during a five-run first inning. (David Kohl/USA Today Sports)

The Washington Nationals’ four-game trouncing of the Cincinnati Reds could be aptly synopsized with the first inning of the series finale, a 6-1 Nationals victory, at Great American Ball Park on Monday afternoon. It began with Washington pounding another helpless Reds pitcher, Scott Feldman, for four straight hits — a double, a single and back-to-back home runs — to produce four quick runs. And it continued with a blooper benefiting, of course, the visitors.

The strange sequence that led to the Nationals’ fifth run was initiated when Reds right fielder Scooter Gennett made a diving catch to rob Matt Wieters of extra bases for the game’s first out. That was the good news for Cincinnati. The bad news was Gennett then tripped and dropped the ball. The lag went long enough for Daniel Murphy, not exactly a burner, to tag up and score . . . from second base.

Murphy’s run assured the first five batters Feldman faced scored after the first six reached base. The barrage chased Feldman, who was battling a knee injury and is expected to land on the disabled list, after just one inning. It was a swift move that proved to be one of the few things that went right for the last-place Reds (39-53) during this rare weekend wraparound series.

Washington scored just once off the Reds’ bullpen, as Asher Wojciechowski relieved Feldman and allowed one run over five innings. But Stephen Strasburg, followed by Joe Blanton and Matt Grace, ensured the margin was sufficient to capture the Nationals’ first four-game sweep since April 2016, their first such sweep against the Reds and their 30th road win.

“We’ve been flirting with sweeps quite a few times but just don’t complete that last game,” Nationals Manager Dusty Baker said. “We jumped [on] them early. I think Feldman probably hurt himself, which helped us, which you hate to see. But at the same time we’re trying to win as many games as we can.”

Stephen Strasburg struck out 11 Reds over seven innings. (Joe Robbins/Getty Images)

Brian Goodwin commenced Washington’s first-inning onslaught with a leadoff double. Stephen Drew then singled before Bryce Harper whacked a three-run home run, his 23rd homer of the season. One pitch later, Ryan Zimmerman, who was given Sunday off, launched a line drive just over the wall in left field in his first at-bat back. The homer, his first since June 13, was the 235th of his career, surpassing Vladimir Guerrero for the most in Expos/Nationals franchise history.

“I think it’s special to be at one place your entire career,” Zimmerman, 32, said. “For me, it’s more about being around the same people and creating relationships, being lucky enough to be able to do that. You can’t do stuff like this if you’re not in the same place a long time.

“I feel very lucky to have spent my entire career here, honored to have hit more home runs than any Expo or National. It’s cool.”

Goodwin added his eighth home run in the sixth inning, giving the Nationals 13 home runs in the series — tied for the second most Washington has ever accumulated in a four-game set. Strasburg was already plowing through the Reds’ lineup by then.

The right-hander started Monday instead of Sunday following Max Scherzer because the Nationals (56-36) set their rotation out of the all-star break wanting to split up their two most consistent innings eaters. Any combination, it turns out, would have worked. Coming off his worst start of 2017 nine days earlier, Strasburg yielded a solo home run to Eugenio Suarez in the second inning. It was the first and only earned run Nationals starters surrendered all series. Battling the heat, his kryptonite, Strasburg didn’t let any other Red reach second base during his seven innings.

“It shows what kind of shape Stras is in because he sweats a lot and he’s usually not real, real good when it’s hot,” Baker said. “So you can tell he’s really been working and training to deal with this heat. He was very good today.”

Strasburg allowed four hits total and walked one. He coaxed two inning-ending double plays. His fastball touched 99 mph, and his change-up provoked frustration. The dugout grew concerned that he was cramping, a common occurrence for Strasburg on hot days, in the seventh inning. Pitching coach Mike Maddux walked out to make sure he was fine, but Strasburg shooed him off and finished his day with three straight strikeouts for 11 total.

“It just took a little while to get loose,” Strasburg said. “Just felt like a couple days of no-throw over the break, just kind of the body wants to pretend like it’s the offseason. . . . It just took a little while, but I tried to battle through and keep going and it seemed like it got better as the game went on.”

Strasburg exited after 105 pitches and Blanton replaced him to pitch a scoreless eighth, extending his scoreless innings streak to 7⅓ . Grace was then called on for the ninth and dismissed the Reds in order. It was the kind of late-game tranquility the Nationals have not enjoyed often enough this season, which prompted them to trade for Sean Doolittle and Ryan Madson on Sunday.

By the end, the Nationals, still with three regulars on the disabled list, had outscored the Reds 35-12 over the lopsided four-day encounter. They never trailed in the series. They now head to Anaheim, Calif., with a five-game winning streak, a comfortable division lead and the third-best record in baseball.

A couple of vital bullpen upgrades will be waiting. The Nationals, already dangerous, are about to get better.