OAKLAND -- Daulton Jefferies let out a roar and a fist pump as he walked off the Coliseum mound following a swinging strikeout of Brandon Marsh to end the top of the second inning.

That type of excited demonstration is common for most pitchers. It’s atypical, however, for Jefferies, who is generally a mild-mannered and reserved presence. Having grown frustrated with his recent performances, though, the A’s right-hander took a new demeanor out to the mound in Friday’s 2-0 loss to the Angels.

“I showed a little bit more emotion,” Jefferies said. “The last couple outings weren’t my best, so I just really wanted to go out there and show that I can still compete. I know that I’ll get knocked down, but I’m gonna get up every single time.”

A star-studded Angels lineup brought out something extra in Jefferies, whose fastball averaged a tick above his season average at 93.4 mph and maxed out at 95.2 mph. He was able to turn that adrenaline into positive results, keeping the A’s in the ballgame by limiting the Halos to just two runs on five hits and no walks with four strikeouts across six solid innings.

Entering Friday, Jefferies had allowed 15 runs in 14 innings pitched over his previous three outings. The groove he found himself in against the Angels was more reminiscent of the early success he enjoyed last month, when he yielded just two earned runs over his first three starts of the regular season.

“It looked like he had a little different mindset,” A’s manager Mark Kotsay said of Jefferies. “There was a little bit of emotion behind him on the mound tonight. I think he had a good game plan and attacked hitters down in the zone, which is his strength. His fastball had good life on it tonight and he mixed in a lot of good changeups.”

Seeking a remedy to his recent rough stretch, Jefferies smartly made a concerted effort throughout the past week to pick the brain of rotation mate Paul Blackburn, holder of a team-leading 1.74 ERA through six starts. The main takeaway from those conversations for Jefferies was Blackburn’s method of pitching out of the stretch as opposed to the windup for the entirety of his outings. With that insight, Jefferies decided to employ that same strategy on Friday.

Utilizing that Blackburn technique, Jefferies got himself back on track. He pitched aggressively to hitters and produced 46 swings and nine whiffs (swings-and-misses) on his 88 total pitches, usually a sign that he’s at his best.

“Talking to Paul, he goes from the stretch the whole time,” Jefferies said. “I just felt more controlled and driving down the mound. From the windup, my momentum and my energy was kind of inconsistent. I just tried to be as consistent as possible and attack guys.”

As Jefferies progresses through his rookie season, Friday’s outing could be one to look back at as a springboard. Rather than stress over the daunting task of facing world-class hitters like Mike Trout, Shohei Ohtani and Anthony Rendon, he embraced the challenge and fared well.

With his only real mistake of the night a solo home run given up to Andrew Velazquez in the fifth, Jefferies handled the trio of Angels stars quite nicely, holding Trout, Ohtani and Rendon to 1-for-9 with a pair of strikeouts.

“It’s a blast,” Jefferies said of facing the daunting Angels offense. “Those guys are two or three of the best guys in the game. Why wouldn’t you want to go against the best? That’s what being in the Major Leagues is all about.

“Going out and competing. Showing you can hold your ground against these guys, that gives me a lot of confidence going forward.”

The A’s offense will look to reward such outings by Jefferies going forward a bit more than it was able to on a night that it only collected a pair of hits -- both from Elvis Andrus. Most of those inefficiencies at the plate were caused by a terrific Major League debut by Chase Silseth, whom the Angels called up from Double-A earlier in the day.

Swinging early and often against Silseth, who tossed six shutout innings, the A’s ended 21 of their 30 plate appearances on the night in four pitches or fewer.

“I think you've got to give [Silseth] credit,” Kotsay said. “Kid did a great job attacking us. Life on his fastball. Split was really good. His tempo was amazing. He had a plan and he was on the mound ready to go. You’ve gotta tip your cap when you have a performance like that, especially from a young kid making his Major League debut.”