Sam Kessler thrives off the fear he instills in hitters.

“I look in the batter’s eyes, and I see their fear,” the Mount Sinai pitcher said. “They don’t know what’s coming next.”

Kessler used his high-octane fastball and wipeout slider to keep batters uneasy during a historic season for the Mustangs, who won the Long Island Class A championship for the first time. The big righthander went 8-3 with a 0.39 ERA en route to being named the 2016 Paul Gibson Award winner.

HistoryHigh school sports awards history

The Gibson award is given each season to the most outstanding pitcher, as voted by the Suffolk County Baseball Coaches Association.

Mount Sinai coach Eric Reichenbach raved about Kessler’s makeup, citing his growth before his senior season.

“I knew this kid had talent when he came to me as a ninth grader, but it took him three years to make the transition from being a thrower to being a pitcher,” Reichenbach said. “This is the year, he put all of that together.”

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Despite having a low 90s fastball at his disposal, Kessler continually worked in the mid 80s to conserve energy. Then when he needed extra juice, Kessler was able to rear back and blow his fastball by hitters.

“I learned that I had to conserve — it’s a marathon not a sprint,” he said. “I can get away with 87 here and there and then if I have to, throw a hard fastball, so I’m not drained by the seventh inning.”

Sacrificing velocity didn’t slow Kessler. He still struck out 95 batters in 72 1⁄3 innings, thanks to a devastating slider that he can locate in the zone or throw in the dirt for swinging strikes. He walked 14 batters this season.

“The first time I learned that pitch was when I was nine,” he said. “It was never stress on my arm. Over the years, it just developed to what it is now.”

Kessler’s season was bookended by stretches of dominance. He didn’t allow a run — earned or unearned — until his fifth start of the season, a 1-0 loss to Bayport-Blue Point.

He then closed the campaign by allowing no earned runs in four playoff starts spanning 30 1⁄3 innings.

“That’s the best stretch I’ve ever seen from anyone in 20 years at Mt. Sinai,” Reichenbach said.

Kessler will pitch at West Virginia next season, where he said coaches have given him an indication that he might have the opportunity to be an immediate contributor.