Ian Desmond (20) is greeted by Nate McLouth after his seventh-inning blast to left field. (Toni L. Sandys/The Washington Post)

As the Washington Nationals fought a confluence of forces Sunday morning, Ian Desmond waged a more personal battle. Over the winter, he stopped using smokeless tobacco, and he vowed this season he would quit using the substance known in baseball clubhouses as “dip.” It had always acted as a salve after losses, and the Atlanta Braves had beaten the Nationals the past two days.

He sent his mother, Pattie Paradise, a text message from inside the clubhouse. “I’m having a hard time,” he wrote. Having pleaded with him to stop for years, Paradise sent back, “You can do it.”

In the seventh inning, Desmond walked to the plate with the score tied and the Nationals hitless for the past five innings. They were in need of a jolt, trying to salvage a win with a diminished lineup. With one vicious swing, Desmond launched Alex Wood’s fastball 20 rows over the left field fence and lifted the Nationals to a 2-1, sweep-stopping victory over the Braves.

Desmond’s titanic homer, which nearly landed on the concourse, fortified a clutch performance from the Nationals’ pitching staff. In his season debut, Taylor Jordan used his cannonball sinker to limit the Braves to one run over 61 / 3 innings. Relievers Jerry Blevins, Tyler Clippard and Rafael Soriano, who en route to his first save toed the line between excruciating and exciting, held the Braves scoreless.

“I love beating the Braves,” Jordan said. “We needed that. They’re our rivals. It’s great to get one.”

After Soriano fooled Jason Heyward with a nervy, 3-2 slider to strand two runners, Desmond retreated to the clubhouse. By the time Desmond stood in front of reporters, he had made it through the day without a dip.

“That was a bigger victory than beating the Braves,” Desmond said. “I’ve done it for a long time. I’m really trying hard to quit.”

The Nationals, too, had accomplished something. Attrition erodes every roster and tests every baseball team. It just usually takes longer than the season’s first Sunday. The Nationals braced Sunday morning for MRI exam results on Ryan Zimmerman’s balky right shoulder. Scott Hairston joined Wilson Ramos and Doug Fister on the disabled list. Bryce Harper sat on the bench lost in a 3-for-21, 10-strikeout slump. The Braves had asserted their dominance.

“What are we, five games into this?” pitching coach Steve McCatty said before the game. “There’s a lot of time left. It’s baseball. Adapt. Adjust. Overcome.”

The Nationals overcame a lineup that lacked their opening day Nos. 1, 2, 4 and 5 hitters. They started fast — singles from their first three hitters, two of which did not leave the infield, led to an immediate, 1-0 lead. Wood then retired 13 straight and recorded 18 outs without a hit before Desmond came to the plate.

“We needed to score a run there and prove to ourselves that we could hold them down,” Desmond said.

Wood threw an 87-mph, number-high fastball that bisected the plate. Desmond vaporized it, and he knew it. Desmond flipped his bat toward the Nationals’ dugout and skipped two paces down the line. The ball crashed five rows shy of the concourse behind the left field seats, where Desmond remembers Michael Morse’s homers soaring.

“Oh my God,” Jordan said. “I was in the training room. Everyone just started clapping, started cheering. That was a bomb.”

The Nationals led 2-1, an edge Jordan had allowed. Jordan had thrown a simulated game in Florida to stay ready between spring training and his first start. Still, “I felt great,” Jordan said. He deadened bats with his sinker and dodged trouble when it came.

In the fourth, two walks and a misplay loaded the bases with one out. First baseman Adam LaRoche came to the mound and told him: “Your stuff looks great. Keep pitching.”

Jordan had not struck out any batters all game, and he typically aims for quick, soft contact. But with Gerald Laird coming to the plate, “I was definitely trying to go for a strikeout,” Jordan said. He whiffed Laird with a wicked, 91-mph sinker that dived toward his ankles. Jordan escaped in his usual manner, a slow groundball to third base by Andrelton Simmons.

“The sinker was working great,” Jordan said. “It had great movement on it.”

Dan Uggla’s sacrifice fly in the sixth tied it at 1, but the Nationals’ bullpen stopped the damage. Blevins retired both Freddie Freeman and Heyward, two of the fearsome, intra-division left-handers the Nationals had in mind when they acquired him this winter. Clippard got two outs in the eighth to set up Soriano for his first save chance this season.

After two quick outs, the Braves extended the game with two infield singles. Heyward lumbered plateward. Soriano and rookie catcher Sandy Leon agreed they would feed Heyward cutters on the inside corner. The count ran full, and Heyward had timed the cutter.

“Last pitch,” Leon said, “he wanted to throw a slider.”

Soriano twirled the breaking ball down the chute. Heyward swung so hard he nearly fell to a knee. The ball zipped into Leon’s mitt. Soriano untucked his jersey. The crowd exhaled.

“He knows what he’s doing out there,” Manager Matt Williams said. “You got the feeling if he didn’t get Heyward, he was okay with going after B.J. [Upton], too. He doesn’t panic. His heart rate never gets up.”

Desmond could celebrate a win and an achievement. He stopped dipping before December and made it through spring training for the first time since he became a professional 10 years ago at 18. Desmond admitted he broke down Saturday night and packed his lip. But he viewed it as a small hurdle.

“That was back on the wagon, off the wagon,” Desmond said. “It’s not easy. I feel for people who have to deal with this stuff on a larger scale. I’m not proud that it’s got that control over me. But I’m fighting it.

“I hate to say this because I know there’s going to be kids that hear this. For me, growing up, it was part of the game. That’s what it was. When I put my uniform on, I feel like that’s part of what I need to put on. It just goes with the job, for me. I’m trying to shake it off.”

Desmond mother practically begged him not to dip Sunday morning. He had listened, and then he blasted the biggest home run of the Nationals’ first week. It may have been a coincidence, but Desmond will hold on to it. “That’s incentive enough right there,” he said.