His last hitter in the Nationals’ 4-0 win over the Miami Marlins on Saturday afternoon at Nationals Park was Tim Anderson, who had fanned twice. Herz got up 0-2, and Anderson asked for time in a bid to disrupt Herz’s timing. Nothing else worked to that point, so maybe a few extra seconds could rattle the 23-year-old rookie.

No chance. Two pitches later, Herz threw a 93-mph fastball by Anderson for his 13th and final strikeout. And when Anderson swung through the pitch, Herz showed off more than a strut. This time, he turned his back to the home dugout, backpedaled and put his hands out before shaking his glove.

“This outing, I wanted to control my body language a little bit more, be a little better at that,” Herz said. “The first five innings, it was perfect. And then I got the last strikeout, and I kind of had a feeling that I was done. And I just let my emotions fly a little bit.”

Before his start, Herz said he had a conversation with Jake Irvin about wanting to be emotionless on the mound. “I just wanted to go out there and be a stone-cold killer.”

Mission accomplished. The only blemish in his six innings was a Jake Burger single that got past Trey Lipscomb to start the fifth inning. The Nationals (34-36) have won seven of eight and will go for a series sweep Sunday.

Manager Dave Martinez pulled Herz after the sixth. The numbers: one hit, 13 strikeouts, 84 pitches, 57 for strikes. And perhaps most important to Herz: no walks.

“He and [catcher Drew] Millas worked really good and very quick,” Martinez said. “And they did get into that rhythm, and he was feeling it.”

In a Nationals season that will be defined by the growth of the team’s young starters, Herz could be the surprise of the bunch. The team knew Josiah Gray, MacKenzie Gore and Jake Irvin would be big league contributors this season, and Mitchell Parker has been a welcome addition. But Herz, a 6-foot-2 left-hander acquired from the Cubs at the trade deadline last season in the Jeimer Candelario deal, delivered one of the best starts in the majors this season.

Per OptaStats, his 68.4 strikeout percentage (13 of the 19 hitters faced) was the second highest by an MLB rookie in the modern era with a minimum of 15 batters faced, trailing only the Cubs’ Kerry Wood in his 20-strikeout game from 1998. His strikeout total was the most by a Nationals pitcher since Max Scherzer fanned 14 in May 2021.

“Everything was working tonight, so we couldn’t really go wrong,” Millas said.

One more fact from the start that has local appeal: Herz became one of two MLB pitchers with a start of at least 13 strikeouts and no walks in one of his first three outings since 1901 — the other being Stephen Strasburg in his debut June 8, 2010. Pretty good company, especially for a guy who didn’t make it out of the fifth inning in each of his first two starts. He was on a pitch limit in his major league debut. And in the second, it took him 87 pitches to get through 4⅓ innings.

Herz couldn’t consistently throw his best pitch, his change-up, in the zone in his first two outings. But he told pitching strategist Sean Doolittle that he felt different entering this start.

This time around, Herz was efficient in the first four innings as he racked up the strikeouts. He struck out four and threw just 24 pitches in the first two innings. In the third, Herz struck out the side and followed that up with one more in the fourth. He retired the first 12 Marlins before Burger’s single.

“The game didn’t speed up. That’s probably the most calm and relaxed I was,” Herz said. “It’s all about, for me at least, getting comfortable. That might take a little time, but it’s starting to come now.”

The Nationals’ offense jumped out to a 1-0 lead in the first when Lane Thomas doubled, Jesse Winker — who exited in the third inning and will get an MRI exam on his right knee — singled and Joey Meneses hit a sacrifice fly. Thomas hit his second home run in as many days in the third inning to extend the Nationals’ lead. Meneses added a two-run blast in the eighth.

Herz, meanwhile, induced 21 whiffs in 45 swings, including 13 on four-seam fastballs. The Marlins swung through fastballs right down the middle. They watched change-ups paint the corners for called strikes and shook their heads. They chased in the dirt. And as each Marlins hitter slumped back to the dugout, Herz continued to strut.

“I mean, it still doesn’t feel real,” Herz said. “I’m super blessed. That was my probably my best game I’ve ever pitched. And to do it at this level, it’s a great feeling.”

Notes: The Nationals announced they agreed to terms on a minor league contract with outfielder Harold Ramirez, who will report to Class AAA Rochester. Ramirez, 29, is a six-year major league veteran who was designated for assignment by the Tampa Bay Rays last week. He also had stints with the Miami Marlins and Cleveland Guardians. Ramirez hit .313 with 12 home runs and a .813 OPS a season ago but hasn’t produced the same pop this season; he’s hitting .268 with a .589 OPS and only four of his hits have been for extra bases. . . .

Cade Cavalli threw two innings and around 45 pitches in a live bullpen session Saturday afternoon, facing Trey Lipscomb and Nasim Nuñez. Cavalli said his arm felt good as he works his way back from Tommy John surgery.