Adam LaRoche dives in for a double, beating the throw to Twins second baseman Eduardo Escobar in the seventh inning of the nightcap. (Katherine Frey/The Washington Post)

Sunday morning, before the long day ahead, Manager Davey Johnson gathered the Washington Nationals for the “little talk” he had publicly promised the day before. His anger had dissipated by the time he stood in the clubhouse before his players, with whom the 70-year-old cannot stay mad. He spoke for three minutes, all casual banter and no livid spewing. “Just cheered ’em up,” he said.

Johnson told everyone to relax. He urged aggression from hitters and confidence from the entire team. “Not just wait,” rookie Jeff Kobernus said, summarizing Johnson’s message. “But go out and take something.”

The Nationals will have to start somewhere if they intend to play meaningful baseball late into the summer, and maybe that launching point came Sunday in a doubleheader sweep of the Minnesota Twins. It began when Jordan Zimmermann spearheaded a 7-0 throttling in Game 1 and ended with a grinding, rain-delayed 5-4 victory in Game 2, the biggest comeback of the Nationals’ season. In the end — and only after Rafael Soriano’s loss-defying save 20 minutes before 11 p.m. — the Nationals had climbed back to .500 and out of third place, still 71 / 2 games behind the Atlanta Braves but at least ahead of the Philadelphia Phillies.

“I don’t mind the position we’re in,” first baseman Adam LaRoche said. “I was talking to [Jayson Werth] about it. Obviously, it’s nice to be leading. But I also like the fact that every game from here on out, we need to grind it out. We’re in no position to coast. I think we’re going to have to grind down to the final game in September to make this thing happen. I don’t mind being a few games back.”

Zimmermann plowed through the Twins for seven scoreless innings in the afternoon. At night, the Nationals overcame Nate Karns’s shaky start with flawless relief and steady offense, capped with consecutive doubles in the seventh inning from LaRoche and Ian Desmond. They held on after Soriano walked the tying run to bring Joe Mauer to the plate, gave up a single and got former National Josh Willingham to pop up.

Several moments have convinced the Nationals they had halted their spiral, only for them to realize later the bottom was still a few wasted games away. Sunday offered another possible U-turn, wrapped in Zimmermann’s dominance and an offense that, in the nightcap, erased a three-run deficit and won for the first time all season.

“The offense, that’s what I’m talking about,” Johnson said. “That’s what I like to see. We were more aggressive. It was fun.”

After scoring 11 runs in their previous five games, the Nationals scored 12 in two while pounding 24 hits, 14 of them in Game 1. Across both games, Desmond smacked four hits and drove in three runs, including the game-winner in Game 2, running his hitting streak to a career-high 12 games. Rookie Anthony Rendon added three hits and, despite an error in each game at second base, the position he is still learning, made a crucial, leaping catch to save a run in Game 2.

“They don’t just give the Manager of the Year award away,” Desmond said. “Davey’s got a pretty good eye on what’s going on in here and sometimes you just need that freedom from your manager to say, ‘Hey, just go up there, be aggressive and don’t hold anything back.’ He really freed us up.”

Zimmermann made easy work of the Twins, and then Karns made the Nationals work for the sweep. In his likely final start before Ross Detwiler bumps him back to the minors, Karns showed he still requires more seasoning. He both missed wildly and fired fastballs straight down the middle. The Twins drew three walks and ripped three extra-base hits off him, including Pedro Florimon’s two-run homer to right on a 92-mph fastball at the belt. In three starts, Karns allowed five homers over 12 innings, the main contributor to his 7.50 ERA.

The Nationals trailed, 4-1, when Craig Stammen replaced Karns. As he punched up two zeros, the Nationals chipped away. An RBI single from Werth in the third and LaRoche’s sacrifice fly in the fifth pulled them to within one.

Rendon’s leaping, full-extension grab in the sixth saved a run, helping Fernando Abad strand Eduardo Escobar at third base after a leadoff triple. In the bottom of the inning, Rendon poked a single to left to lead off.

After two outs, Denard Span drilled a triple into the right-field corner, scoring Rendon with the tying run. Span clapped his hands when he stood up at third, an emphatic celebration of a clutch hit against his old team. Back in the dugout, Desmond told him, “Now you’re part of the team.”

The Nationals’ completed their comeback in the seventh. LaRoche roped a double to right off Anthony Swarzak. On the very next pitch, Desmond smashed a liner past Willingham in left-center field, giving the Nationals a 5-4 lead. Standing on second base, he threw an imaginary spotlight on the Nationals’ dugout.

“This was probably our best ballgame,” Span said. “Normally, early on in the season when we would get behind we would just fold and give away at-bats. We just kept fighting and having good at-bats.”

Around noon, as Johnson chatted with the team, he looked around the room and saw Zimmermann with a heat pad wrapped around his neck to ward off stiffness. Johnson worried about his ace, but only until he took the mound.

Zimmermann, a steady force in a rocky season, added to his all-star caliber first half with seven two-hit, eight-strikeout, scoreless innings that gave him his ninth win, tying him for the league lead. Their sagging offense finally took advantage when presented with back-of-the-rotation fodder, tagging Scott Diamond for seven runs, five of which scored in the fifth, just the second inning all year in which the Nationals batted around.

With two runners in scoring position and two outs in the second, Twins Manager Ron Gardenhire ordered Diamond, a left-hander, to walk Werth. Rather than face the right-handed hitter who had homered Saturday and already singled twice Sunday, Gardenhire loaded the bases for LaRoche instead.

The intentional walk sparked the Nationals’ highest-scoring inning of the year. LaRoche smacked a single off of second baseman Brian Dozier chest. Desmond roped a single to center. Rob Pressley relieved Diamond, and Rendon blistered a two-run double to right.

Meanwhile, Zimmermann ignored defensive lapses and sailed. After Rendon dropped a pop-up in the third, the right-hander struck out Ryan Doumit to end the inning. When third baseman Zimmerman’s 10th throwing error sailed high, Zimmermann induced a fly to left and a weak grounder to first. He never removed his poker face.

“Just keep pounding the strike zone, and hopefully they put another ball in play and give them another chance,” Zimmermann said. “I just want to give them another chance to get the confidence back.”

Zimmermann lowered his ERA to 2.00 and earned his ninth win. With his 111th and final pitch, he got Chris Colabello to swing through a 96-mph fastball. Zimmermann walked off the mound, his facial expression still stuck on neutral, not responding to raucous cheers.

Zimmermann’s brilliance had given the Nationals another moment to let them believe the worst is behind them. Their road ahead, starting with three games in Colorado, will determine whether Sunday was a springboard or another false sign.

“We’ll see Tuesday,” LaRoche said. “We’ll find out.”