Tanner Rainey had been so dominant, his stuff so sharp, that every break from that has passed without much worry this summer. But a string of recent mistakes funneled into a big one Thursday night, when he yielded a go-ahead homer to Dansby Swanson in the eighth inning of a 7-6 loss to the Atlanta Braves at Nationals Park.

The defeat wasn’t on Rainey. Certainly not all of it. But the deciding swing came on a high fastball that was supposed to be low and away. Swanson, the Braves’ shortstop, jetted around the bases while faint cheers escaped the visitors’ dugout. Rainey circled the mound before calling for a fresh ball. The Nationals had a 5-0 lead before Atlanta chipped away, tagging Austin Voth, Wander Suero, Will Harris and Rainey for runs.

The loss dropped Washington to 16-26 and was a missed opportunity to keep inching up the standings.

“We got toward the later innings, and slowly but surely, the lead kept getting smaller and smaller,” Rainey recounted. “I mean, we saw it happen. Nobody is happy about giving up runs, whether it’s our own or somebody else’s. So blowing that lead there, that’s a tough one.”

Result aside, it was a special night for Manager Dave Martinez. On Wednesday, as the sport honored Roberto Clemente by allowing players and coaches of Puerto Rican descent to wear his No. 21, he’d watched with unbending pride. Clemente was Martinez’s idol growing up as the son of Puerto Rican parents. But since the Nationals were off, Martinez didn’t get the chance to change his number for one game.

He’d worn 21 as a high school football player. But he never did in baseball, feeling, as many Latin Americans do, that Clemente’s number is off limits for all he accomplished on and off the field. Then Martinez had an idea: He and his whole coaching staff would switch to 21 for the series opener with the Braves.

So as the national anthem played through the empty stadium, Martinez, Tim Bogar, Chip Hale and Bobby Henley were by the first base line, shoulder-to-shoulder, each in a white jersey with 21 and no last name on the back. Martinez felt that reflected what Clemente pushed for before his 1972 death in a plane crash while delivering relief supplies to earthquake-ravaged Nicaragua.

“What he represents is unity, and I thought it’d be nice to have the coaches represent 21, as well,” Martinez said Thursday afternoon. “He means a lot to not only the Latin community, but the baseball community for what he’s done. Not only as a player but as a humanitarian.”

Martinez had already made the critical decision of starting Voth again. The righty entered with an 8.26 ERA in seven outings. In his previous appearance, also against the Braves, he allowed five runs in 4 2 / 3 innings. After resting Wednesday, the Nationals could have skipped Voth and still pitched Erick Fedde, Patrick Corbin, Max Scherzer and Aníbal Sánchez on regular rest against the Braves. But Martinez says he never considered it.

For three innings, Voth rewarded that confidence. He retired all nine Braves he faced. He struck out three with a biting curve. He held the Braves down while the offense, charged by Adam Eaton, built a lead. In the first, Eaton singled, Trea Turner tripled him in, Juan Soto doubled in Turner and Asdrúbal Cabrera tripled in Soto. That was three extra-base hits in three batters to rattle Atlanta starter Robbie Erlin. Then Eaton blasted a two-run, upper-deck shot in the second before Erlin was pulled.

But soon Voth stumbled through his second turn through the order. It’s been a troubling theme for him all season. He walked Ronald Acuña Jr. on a borderline fastball to start the fourth, and, a hitter later, Freddie Freeman parked a two-run shot in the right-center seats. He stranded two runners in the inning, wiggling past more damage, yet lasted just two more batters. And when he exited in the fifth, after hitting Tyler Flowers with a pitch and having thrown 83 pitches, Suero’s first pitch flew over the fence.

It was a low cutter. Acuña used it to smack his 11th homer, pulling the Braves within 5-4. The Nationals added a run, on Yan Gomes’s sacrifice fly, but the Braves tied it when Freeman took Will Harris deep in the seventh.

Harris, 36, has been up and down in his first year with Washington. This time, with Martinez needing three outs in the seventh, he yielded a leadoff single, induced a double play and walked Acuña with two outs. That brought up Freeman, who recently hit two grand slams in a four-game series against the Nationals. And that brought another bad result for Harris, who hung a curveball that landed in the second deck in right.

Despite jumping ahead early, the Nationals had stranded eight runners and missed a few chances to bury Atlanta. They didn’t register a hit between the fifth and eighth. Then Swanson took Rainey deep, nudging the Braves ahead for good.

Rainey had allowed just two earned runs in his first 16⅓ innings this summer. But now, after Swanson’s homer, he’s given up four in his past four. The last was enough to edge the Nationals, who watched reliever Sean Doolittle limp off the mound in the ninth. So after a brief respite, having won four of five heading into Thursday, Washington felt the losses roar right back.