NEW YORK -- JP Sears’ first Major League start didn’t begin the way one might draw it up. He walked Orioles leadoff hitter Cedric Mullins on five pitches; then, when he thought he had induced a double-play grounder from Trey Mancini, Yankees second baseman Gleyber Torres bobbled the ball.

Though Mullins was initially called out, the O’s challenged the play and the call was overturned, leaving runners on first and second with nobody out in the inning. It was sink-or-swim time for Sears, the 26-year-old southpaw who had waited five years for a chance in the big leagues.

So Sears reared back and threw three straight fastballs past Anthony Santander. He forced Austin Hays to sky a popup to shortstop on an 82 mph slider. And when Ryan Mountcastle wouldn’t bite on three pitches outside the zone, Sears threw three fastballs for strikes, then punched him out looking with an 85 mph changeup.

Sears had made it back to the safe harbor of the home dugout, and his outing went off without a hitch from there. He tossed five scoreless innings with five strikeouts and helped the Yankees earn a series victory over the Orioles with a 2-0 win on Wednesday night at Yankee Stadium.

“You see how good his fastball is, but I thought his secondary was really competitive, too -- both the slider and the changeup,” said manager Aaron Boone. “Got into some trouble a couple of times, sometimes not necessarily by his own doing, and he was able to make pitches. … To give us five, shutting them down, and especially when he faced a little bit of adversity early -- it was huge for us.”

The Yankees’ No. 23 prospect per MLB Pipeline, Sears was called up from Triple-A Scranton/Wilkes-Barre just to make Wednesday’s start. After the Yankees dealt with a rainout last Friday and played a doubleheader Sunday, he started to realize he could have an opportunity to make a spot start for the big league club.

Sears had begun the season in the Yanks’ Opening Day bullpen, making his first two Major League appearances in relief on April 13 vs. the Blue Jays and April 16 vs. the Orioles. He allowed just two hits in two innings and even earned his first win against Baltimore. But Sears was sent down the next day -- because the Yankees wanted him to stretch out as a starter.

Sears found much success in the role, posting a 0.83 ERA in 21 2/3 innings made up of six outings (four starts) with the RailRiders, with 30 strikeouts against just two walks.

“He’s obviously thrown the ball really well to earn this opportunity,” Boone said. “… To see him come up and step up in this way, it’s just kind of a continuation of what he’s been doing down there, really.”

With days to prepare, Sears had quite a crowd in attendance at Yankee Stadium, including his father Pat, mother Suzann and longtime girlfriend Aileen, as well as about 15 friends. They watched as he found more and more of a groove as the outing progressed -- including an impressive four-pitch inning in the fourth to counteract the 50 pitches he had thrown through the first two frames.

He induced a pair of popups in foul territory, then a bunt groundout to batterymate Kyle Higashioka. Just like that, back in the dugout he went.

“I definitely felt more comfortable as I went,” Sears said. “It was one of those outings where I felt better each inning I was out there. It was definitely sharper each inning I was out there. Making some good pitches and getting some swings earlier in the count.”

Despite his spotless start, Sears was optioned back down to Triple-A after the game. He remains on the 40-man roster, where he has been since last November, when the Yankees opted to protect him from the Rule 5 Draft.

That’s the nature of life as a “fringe guy,” and Sears knows that all he can do is prepare himself for the next time he receives the call.

“Mentally, I think that, especially in Triple-A, you’re pitching every time like you’re about to pitch in the big leagues,” Sears said. “So that whenever you get called up, it’s not a surprise. So that’s been going through my mind every single outing in Scranton and here. So it’s just about the next one, always.”

Though the next one likely won’t be at the big league level, Sears proved that whenever the next opportunity arises, he’ll be ready.