WAILUKU >> He’s not exactly a hulking menace on the mound.

Somehow, sophomore Ryan Ancheta managed to become one of the greatest giant slayers in Mililani baseball history. The youngster permitted just one hit in six innings and Koa Eastlack hurled a scoreless seventh as unseeded Mililani shocked No. 1 Mid-Pacific 4-0 on Thursday night in the quarterfinals of the Wally Yonamine Foundation/HHSAA Baseball State Championships at Iron Maehara Stadium.

Mililani (12-5) entered the tourney as the sixth-place team out of the OIA, but Ancheta’s brilliance helped pave the path to the semifinal round. He said he never threw the same pitch twice in a row.

“All my teammates, before the game, told me, ‘Hey, if you pitch tomorrow, just prepare.’ I throw a fastball and a curveball, and a slower fastball,” the 5-foot-4 left-hander said. “I’m humbled. It feels great beating the ILH champions.”

Mililani will battle another OIA West rival, Pearl City, in a 4:15 p.m. matchup. OIA West teams are a combined 9-1 in D-I and D-II state-tourney play.

Mid-Pacific (16-5) made it an 0-2 mark for the private-school league from Oahu in the D-I state tourney.

“It’s just team chemistry,” said Mililani first baseman Aris Nakagawa, who belted a two-run double in a key fourth inning. “Everyone’s on the same page. We know we’re the underdogs and we have nothing to lose. We give 100 percent.”

Coach Mark Hirayama has been preaching the virtues of discipline at the plate all season. It’s paying off this week.

“It’s a special time of year. It’s maturation. It’s refreshing to see the growth. Hopefully, they continue that,” Hirayama said. “(Mid-Pacific starter Alex) Oley is one of the top pitchers in the state. We had to stay with our approach and look for our pitches, cut down on our swings. Earlier in the year, we didn’t execute those things.”

Oley was powerful at the start, striking out three in the first two innings. Oley and Ancheta locked horns in a pitchers’ duel that was scoreless for four innings.

The Trojans scored all four runs in the top of the fifth. With one out, Sheldon Lee, Blaine DeMello and Ryan Kono singled to load the bases. The count was 2-2 on C.J. Ibara when Oley uncorked a wild pitch, permitting Lee to score from third base.

After Ibara’s walk re-loaded the bases, DeMello came home on a groundout by Kaimana Souza-Paaluhi, and the Trojans led 2-0.

Then came a blast off the bat of Nakagawa to the left-field corner. His double brought home Kono and Ibara for a 4-0 lead. After Oley walked Hunter Kirihara, he was replaced by Chase Wago, who pitched 21⁄3 scoreless innings the rest of the way.

The damage was already done. After getting Jacob Maekawa in scoring position in the first inning, the Owls didn’t get past first base again the rest of the afternoon. By the time Ancheta left after the sixth, he had not struck out a batter, walked four, and threw an economical 68 pitches.

MPI got a runner on base in the bottom of the seventh when Kyle Layugan reached on a throwing error, but Eastlack then retired Trevin Tengan on a grounder and Zack Gushiken on a flyout.