ANAHEIM -- The Pirates came into Angel Stadium on Monday night having dropped eight straight games, never really looking in sync during that stretch. But everything finally clicked for them in the series opener, in no small part thanks to the efforts of right-hander Mitch Keller.

In the first start of his second Major League stint, Keller allowed two runs (one earned) over five innings and was backed by four home runs in a 10-2, skid-ending victory. Pittsburgh’s top prospect gave up five hits, two walks and hit a batter while striking out four.

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“It’s incredible,” said Keller. “Growing up, I would never picture being here, where I’m at right now. It feels good to get the first [win] out of the way. Hopefully, many more to come, and with this team, hopefully a lot more success.”

Ranked by MLB Pipeline as the No. 28 prospect in baseball, Keller struggled mightily over three starts in his first callup, getting tagged for 14 earned runs and 21 hits in 12 innings. Monday night was a truer representation of what he’s capable of.

“I don’t know if I felt really anything different. It was just kind of a confidence thing,” said Keller. “I know I belong here, and I know I can do it. It’s just a mindset of, ‘Here’s my best stuff. Try and hit it.’”

It helped that Keller had a lead to work with before even setting foot on the mound, with his teammates taking advantage of some sloppy Angels defense to put up a three-spot in the top of the first. It turned out to be all Keller would need.

“Whenever we’re scoring runs is awesome as a starting pitcher, for sure,” said Keller. “Going out there with a three-run lead right off the bat there. It doesn’t change the way I was pitching. I would’ve pitched the same way if it was 0-0 going out there. But, yeah, it’s definitely a good feeling, all the time.”

Keller worked in and out of trouble for most of the night, managing to limit the damage when runners reached base. Things got interesting in the fourth when the Angels loaded the bases with one out, but Keller escaped the jam with just one run scoring on a sacrifice fly. The unearned run scored as the result of an error by third baseman Pablo Reyes in the fifth.

“The thing that jumped out was the the number of first-pitch strikes, 16 out of 23,” manager Clint Hurdle said. “The sequencing of the pitches was probably the most encouraging part for me. I think [catcher Jacob Stallings] did a fantastic job of calling the game that he needed to pitch tonight.”

Keller’s return to Triple-A also gave him a chance to work on things that had been ineffective for him during his first go in the big leagues -- particularly, his offspeed pitches.

“One of the messages when I got sent down was, ‘You need to be better with the offspeed,’ in zone, out of zone, for really everything,” said Keller. “So I took that and went with it and really challenged myself down in Triple-A to attack those hitters with my offspeed and to get comfortable throwing it behind in the count, ahead in the count and for put-away.”

Through five innings, Keller’s pitch count got up to 91, with 100 being the most he’s thrown at any level this season. At that point, he was removed for Chris Stratton, whom Hurdle had listed pregame as a potential long-relief option. Stratton and closer Felipe Vazquez combined to shut down the Angels over the next four innings.

“We’re just trying to win here, and each game you go out and compete the best that you can, and you know, you hope for the best,” said Stratton, who threw three scoreless frames against his former team. “But it’s obviously great when you can contribute to a starter and help get him his first win.”

The Pirates plan to keep Keller on the 25-man roster for the remainder of the season, meaning he’ll have several more opportunities to prove himself in the Majors. Monday’s outing was a good starting point for the 23-year-old.

“He looked more confident and he looked more comfortable,” said Hurdle. “We’ll see how he continues to progress as we continue to give him the opportunity.”

For someone who’s going to be a vital part of the future of his organization, the first win is just one small step in what Keller and the Pirates hope is going to be a long, productive relationship. But in the here and now, it’s cause for celebration for Keller, his teammates and his loved ones -- that includes his family watching back home in Ceder Rapids, two hours ahead of California time.

“I’m sure my family is having a pretty good time right now,” said Keller. “It might hurt that it’s a Monday night, but I’m sure they’re having a good time.”