WASHINGTON -- One month since left-hander DJ Herz made his Major League debut on June 4, he already has two starts with 10-plus strikeouts and zero walks on his résumé.

“Continuously pounding the zone, pounding the zone, attack[ing],” said Herz, ranked as the Nationals’ No. 12 prospect, after Washington’s 7-2 loss to the Mets on Tuesday at Nationals Park. “And then making them beat me -- not me beating myself.”

Herz previously struck out 13 and issued no free passes on June 15 against Miami. He joins Stephen Strasburg as the only two pitchers to have two outings of double-digit strikeouts and no walks in their first six big league starts (since at least 1901).

He also is only the fifth pitcher to record multiple starts with that pitching line this season, joining Tyler Glasnow (three times), Bailey Ober (twice), Zac Gallen (twice) and Garrett Crochet (twice).

“I’m just going out there and pitching,” Herz, 23, said. “For me, I just want to get deep into games and put these guys in the best situation to win. It’s cool to hear all that stuff that comes with it, but I’m just trying to go out there and do what’s best for my team.”

Herz was locked in over 5 2/3 innings, his second start of five-plus frames. With five hits allowed on the night, he did not surrender a run until a solo homer by Francisco Lindor off a 93.6 mph fastball to lead off the sixth inning.

“Mechanics are good, everything’s controlled, he’s hitting his spots and he’s actually making those guys hit, swing early,” said Nationals manager Dave Martinez. “That’s the key, is get them in swing mode and he’s done that.”

Herz delivered a career-high 92 pitches, surpassing his previous mark of 87 on June 9 in 4 1/3 innings against the Braves. His four-seamer, which he threw for 47 percent of his pitches, reached 96.3 mph and averaged 94 mph (one mile per hour faster than his season average).

"I thought the fastball had life, especially arm-side,” said Mets manager Carlos Mendoza. “But then the way he was using the changeup, the cutter, he kept us off balance. We had a hard time getting to the fastball, and he got ahead. Credit to him, he was on today, he got ahead, and then using all of his pitches, he made it tough on us."

After striking out 13 Marlins batters on June 15, Herz credited advice he received from right-hander Jake Irvin. This week, he spoke with veteran righty Trevor Williams (who is rehabbing on the IL) to seek insight before facing Williams’ former club.

“Take a mental picture of [the strike zone] and then take your eyes off [it], so when you see it again you’ve already got a picture of it,” Herz recounted Williams telling him. “I thanked him for that. That was awesome for me to kind of learn.”

With Herz’s performance, the Nationals’ pitching staff has fanned 10-plus batters and allowed no walks in five games this season, tied for the Major League lead with the Phillies. But for the second night in a row, the Nats lost amid a flurry of Mets scoring in the 10th inning.

“He was going after the hitters,” Martinez said. “We talk about it all the time: it was all pretty much fastball, changeups. He only threw a handful of breaking balls, which was great. He’s in and out, up and down. When he can do that, his changeup’s effective. Kid’s been awesome, he’s getting better and he’s starting to learn a little bit of who he is.

“We’ve got a good starting rotation, they’re keeping us in games, we’ve just got to score some runs.”