ANAHEIM -- After shining in a relatively low-stress Major League debut at the Oakland Coliseum last week, Mason Miller immediately got a taste of what it’s like to battle adversity at the highest level in his second career start.

Miller nearly did not make it out of the first inning of the A’s 5-3 loss to the Angels on Tuesday at Angel Stadium. Facing a Halos lineup that seemed ready to pounce on his electric fastball, the right-hander allowed four runs in an opening frame that saw left-hander Sam Long warming up in the A’s bullpen before Miller finally ended it with a strikeout of Matt Thaiss on his 39th pitch.

“It was stressful in every way for us,” manager Mark Kotsay said. “A young arm on the mound and trying to get him through that. That was his last hitter, really.”

Aware of the necessity for innings to ease the burden on a taxed A’s relief corps that was coming off the previous night’s wild 10-inning contest, Miller locked in and pitched more in the manner of his ranking as Oakland’s No. 3 prospect. 

Following the shaky first, Miller retired nine of his final 10 batters faced, finishing after four innings on 86 pitches as he allowed four runs on five hits and a walk with six strikeouts.

“You’ve got to be impressed,” Kotsay said of Miller’s resilience. “He bounced back and gave us four innings. The positive there is he settled in and went three scoreless. We talked about his process and what to learn and take from this game.”

Miller’s stuff in the first wasn’t all that different from what the A’s saw in his debut outing. He attacked hitters by pounding the zone, with 23 of his 39 pitches going for strikes. The issue was that Los Angeles had identified where Miller was looking to locate his pitches and ambushed him the other way, with three of the four hits in that inning going to right field.

Returning to the dugout to regroup, Miller adjusted his plan of attack by throwing more to the inner part of the zone and getting inside on hitters.

“Just making guys a little more uncomfortable so they can't sit zones that they know I want to throw to,” Miller said of his adjustment. “I was confident in my pitches that I threw there, but these guys are professional hitters. A lot of stuff that maybe I was able to get away with before, that’s not going to be the case now.”

After lighting up the radar gun in the first with 12 pitches that registered at 100 mph or higher, Miller took a bit off his velocity, at least for his standards. From innings two through four, Miller eclipsed 98.9 mph just four times as he worked to locate his pitches better. Still, the stuff was plenty powerful, as Miller finished with an average velocity of 98.6 mph on his 54 fastballs thrown.

Squaring off against Mike Trout again in the second after the superstar sparked the four-run first by turning on a 100.7 mph fastball for a ground-rule double, Miller exacted some revenge with a swinging strikeout on a 99.4 mph four-seamer. One batter later, he spotted a 98.3 mph fastball that froze Shohei Ohtani for strike three.

“I’m proud of that, for sure,” Miller said. “Trout got me in the first inning and kind of started that whole snowball there. To come back in the second inning and strike him out and then get Ohtani looking the next batter, that’s all stuff that I think I can be proud of.”

Though Shea Langeliers’ booming 426-foot solo shot and Jordan Diaz’s pinch-hit RBI double inched the A’s closer in the later innings on Tuesday night, Miller’s one bad inning was too much to overcome. The 24-year-old does, however, walk away with a valuable learning experience as he continues his growth at the Major League level.

“I’m upset that our guys came out in the top of the first and got me a run and then I went out there and gave four right back,” Miller said. “I think it’s easy to have an inning like that and fold and go back out not confident in your stuff. But besides early in counts, I felt like I was making my pitches. … I’m going to try to take the positives from today and build them into the next outing.”