LOS ANGELES -- Rookie seasons are marked with all kinds of firsts. For Jordan Yamamoto, his outing on Sunday at Dodger Stadium included some less-desirable ones.

In his seventh Major League start, Yamamoto was charged with five runs en route to his first loss as the Marlins dropped the series finale to the Dodgers, 9-0. It was his first time giving up a home run, and his first time allowing more than two earned runs in a game. The Marlins have now been swept in eight three-game series this season.

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“[I’m] very frustrated,” said Yamamoto. “It just kind of sucks that I couldn’t give the team the best chance to win. Going out there, just letting home runs happen, it’s just one of those things that I’m more pissed off at myself than anyone right now.”

Yamamoto, ranked by MLB Pipeline as the Marlins’ No. 18 prospect, jumped straight from Double-A to make his Major League debut on June 12. And he began his career on a tremendous note, posting a 1.59 ERA through his first six games. He’d yet to have a test like the one the Dodgers presented him, though.

A pitcher skilled at suppressing home runs, Yamamoto found himself going up against the team that leads the National League in them. Across parts of six Minor League seasons, Yamamoto had a rate of 0.7 home runs allowed per nine innings; for comparison, the MLB average this season is 1.39. After not allowing any home runs through his first six starts, he gave up a pair of two-run blasts on Sunday, to Max Muncy in the first inning and Joc Pederson in the third (both lefties).

Manager Don Mattingly attributed the homers to Yamamoto missing his spots.

“Muncy, it looked like he was trying to get in, leaves it out over,” said Mattingly. “Joc, he was trying to go away, pulls it back in.”

Sure enough, command was an issue for Yamamoto all game. Of his 91 pitches, just 51 went for strikes. Walks continue to be a problem for him, as he’s now walked at least two batters in each of his first seven starts. And once again, he got into trouble in the first inning, when he issued a walk, threw a wild pitch and gave up a home run. He’s now allowed more runs in the first (four) than in any other inning.

What does he think is behind those struggles?

“Lack of focus, lack of commanding pitches, lack of just everything,” said Yamamoto. “I have some games where I’m good out of the gate, but some days, I’m just terrible. Today was one of those terrible days.”

Between the home runs allowed and the inability to go deep into the game, it was the toughest outing that Yamamoto has endured as a Major Leaguer so far. But Mattingly knows his pitcher will take the opportunity to grow from it.

“Jordan will be fine,” said Mattingly. “He’s pretty good at self-evaluation and knowing that he made mistakes with location. … Jordan’s a pretty unique kid, from a standpoint of his demeanor.”

For Yamamoto, it’s a matter of figuring out how to avoid the same mistakes going forward.

“You learn more from bad games than you do from good games,” said Yamamoto. “I can take a lot from this game. It’s a learning experience. It’s one of those games that you just gotta figure out -- go back, look at video, talk with the coach and talk with the catcher on what I need to fix, and we’ll go from there.”