LOS ANGELES -- It’s hard to imagine a taller task for a first Major League start than what Mitchell Parker was given on Monday night. Called up to pitch in place of the injured Josiah Gray, Parker was charged with taking on the Dodgers -- and on Jackie Robinson Day at Dodger Stadium, no less.

Parker responded by throwing five innings of two-run ball in the Nationals’ 6-4 win, striking out four and walking none.

It was the first win by a Nationals rookie starting pitcher in his debut since Stephen Strasburg on June 8, 2010.

“I think we're moving further away from it sinking in,” said Parker. “[I’m] taking a minute by minute. We're working on it. But it's starting to get there.”

Stepping on the mound for the bottom of the first, Parker -- the Nationals’ No. 21 prospect, per MLB Pipeline -- was greeted by a run of three MVPs, starting with Mookie Betts. He immediately challenged Betts with a four-seamer over the heart of the plate, a called strike. After a couple of curveballs, Parker got Betts swinging on a fastball up in the zone for his first career strikeout.

In the stands was a cheering section of Parker’s family and friends, including his parents, Tom and Wendy, and his fiancée, Hayleigh Patterson. Television cameras caught a visibly emotional reaction from Wendy after Betts went down swinging.

“It’s the verification of a lifetime journey,” Wendy said of her son, a fifth-round Draft pick by the Nationals in 2020. “[It’s] justification that he belongs here. That it's not a fluke.”

The elation was temporarily put on hold when Parker allowed his first hit -- a Shohei Ohtani single -- and his first run, which came in on a Freddie Freeman double and Will Smith’s sac fly. Parker gave up another run the next inning on a double and a pair of flyouts.

But from there, he settled into a groove, highlighted by a particularly impressive bottom of the third. Facing Betts, Ohtani and Freeman for a second time, the left-hander retired the side, getting Ohtani swinging on a 2-2 curve in between lineouts from Betts and Freeman -- a pivotal moment for Parker as well as his family.

“Speechless,” Patterson said.

“Speechless,” Wendy concurred. “No words.”

Parker worked around a leadoff single in the fourth and pitched a perfect fifth inning, punctuated by another strikeout of Betts to bring his night to a close. Of his 81 pitches, 52 went for strikes.

He relied mostly on his four-seamer/curveball combination, though in the later frames he started sprinkling in his splitter, a pitch he hopes to continue honing in the future.

“After the first inning, he seemed like he kind of settled down, and by the fourth inning, he was like, ‘Hey, let's go,’” said manager Dave Martinez. “... Then we went up to him in the fifth inning just to see how he was. He wanted to go back out, which says a lot. But you have to be smart. He was at 80 pitches. I thought that was plenty. He gave us five good innings.”

It was an exciting end to a whirlwind couple of days for Parker, who first found out he was getting the callup from Triple-A Rochester manager Matthew LeCroy on Saturday afternoon in Buffalo. By Sunday afternoon, he’d joined the Nats in Oakland, while his family scrambled to make travel plans -- though, of course, they wouldn’t have missed it for the world.

“This is what he's been working for the entire time I've known him,” said Patterson.

“Twenty years, we’ve waited for this,” added Wendy.

But this is also just the start for Parker. Added to the Nats’ 40-man roster in November to protect him from the Rule 5 Draft and coming off a strong Spring Training, he was a natural fit to take Gray’s place in the rotation. And with Gray (right elbow/forearm flexor strain) out for likely a couple more weeks, there could well be more opportunities for Parker at the Major League level right away.

For now, though, Parker will appreciate getting a successful debut out of the way.

“It was a really good lineup, and all those guys are very, very good,” said Parker. “So the whole game is going to probably stick with me for a very long time.”