Jacob Young and Mitchell Parker lift the Nats to a sweep of the Marlins

But those two were the primary reason the Nationals beat the Miami Marlins, 3-1, on Sunday afternoon at Nationals Park to complete a three-game sweep. Parker, a rookie left-hander, allowed one run in six innings, trimming his ERA to 3.06 through 12 major league starts. And Young, a rookie center fielder, hit the go-ahead solo home run, the first homer of his major league career.

“It was definitely a blackout moment and something you’ll never forget,” Young said.

Ildemaro Vargas added a sixth-inning RBI double for the Nationals (35-36), who have won eight of nine. They’re 7-0 against the last-place Marlins (23-48) this year after going 6-26 against Miami over the previous two seasons. And the Nationals’ starting pitchers have allowed two or fewer earned runs in 10 consecutive games, the longest streak in the majors.

“Everyone’s throwing well,” Parker said. “It’s contagious. We keep winning ballgames.”

Entering the season, for the Nationals to improve, it was obvious that shortstop CJ Abrams, second baseman Luis García Jr. and catcher Keibert Ruiz needed to make progress. On the mound, Josiah Gray, MacKenzie Gore and Jake Irvin were the names to follow.

All of those players remain important to the rebuild. But in the middle of June, there are others to discuss. That’s significant for an organization that’s still looking for major league contributors. Young has 1.2 wins above replacement per FanGraphs, the fifth most on the team, and Parker ranks seventh at 1.0.

When spring training ended, it seemed Jackson Rutledge and Joan Adon, both of whom were in the six-man rotation at the end of 2023, had a leg up on Parker. Rutledge impressed in the spring. Adon had more experience than both and was called up first when Gray went down with an arm injury. But Parker, a fifth-round draft pick in 2020, has blossomed since he made his debut in April.

Sunday was the latest sign of growth. In his brief major league career, the 24-year-old has relied primarily on a fastball and a curveball. But he didn’t have a feel for his curve Sunday, so he went to his splitter — which he threw just 17.1 percent of the time entering the day — 27 times on 85 pitches (31.8 percent). The Marlins had just two hits against the splitter and managed six over his six innings.

“The first day he came up here … his splitter was not good,” Manager Dave Martinez said. “We told him to do away with the splitter because it’s not working. … Today, it was the opposite. He didn’t feel good with his curveball. He threw a couple good ones, but other than that, his splitter was really good, so he relied on that splitter a little bit more.”

Parker’s most notable flaw, at least in his past two outings, has been an inability to field his position. An error in his previous start led to a four-run inning for the Detroit Tigers, but the Nationals rallied to a win anyway. On Sunday, he made a fielding error to open the second inning but retired the next three Marlins. In the fifth with two outs and a runner on third base, the Marlins’ Jazz Chisholm Jr. hit a tapper to the right side. Parker sprinted to make the play, reached to grab the ball with his glove — and missed it. It was ruled a hit with the speedy Chisholm charging down the line, but the Marlins had tied the score at 1 after Lane Thomas homered in the first inning.

Young led off the fifth by launching a Jesús Luzardo fastball to left-center. The 24-year-old has proved to be an elite defender, but he is by no means a power hitter — he has a .329 slugging percentage in his career and had gone 324 major league plate appearances without a homer. That could limit his ability to be an everyday contributor.

But Young thought he hit this one well, and he was right: The ball hit the back wall of the Marlins’ bullpen. His teammates, who had been needling him about his home run total, spilled out of the dugout as Young sported a big grin while rounding the bases.

“I’m happy I can kind of put that one behind me and give it to them back now,” he said with a laugh after his 93rd major league game.

Young is far from Washington’s highest-touted outfield prospect. The Nationals have James Wood and Dylan Crews knocking on the door. That position group is their deepest in the minors, but that doesn’t matter at the moment. Parker and Young, lesser-known names when this season opened, are proving to be valuable contributors.

“These guys put the work in,” Martinez said. “They really did everything they needed to do for us to say: ‘Hey, wait a minute. Let’s call this guy up. I think he can help.’ … And now they’re here and they’re continuing to do what they did down there before we brought them up.”

Note: Outfielder Jesse Winker, who exited Saturday’s win with a right knee injury, said his MRI exam revealed no structural damage. He said the knee is stiff and he will need a few days of rest but he hopes to be back in the lineup soon.