Sachem North softball is reveling in a first-time milestone as the team boasted its best league record with a 15-4 season. “You kind of don’t realize what you’re in until it’s over,” manager Ken Sasso told The Post. “But when we won that 15th game, and I looked back at our record, I’m like, ‘Wow, we never won 15 games in-league.’ ” Sophomore catcher Delaney Mathes is hitting an unfathomable .685 heading into a playoff matchup with Half Hollow Hills on Friday. Mathes isn’t thinking about personal accolades, though — especially after a second-round exit against Sachem East last season. “I definitely want to win the county … especially just to make it farther than last year would be really great,” she said. The team wants to follow suit with the high-octane energy it’s known for. “There’s never a down moment,” third baseman Brooke Giordano said, with junior pitcher Dani Brennan (left) adding that things reach a fever pitch when the bats are hot. “Everyone is always on the fence and we’re always cheering,” she said. “That’s what makes us different from the other teams, because I don’t think they cheer as well as we do.” Sachem balances spirit with composure as coaches focus “more on the mental part over mechanics,” said junior shortstop Bella Kriklava, who is thrilled to try to win it all. “They’re helping us stay in the right state of mind.” The Class B softball title series starts with the top seed, Carle Place (16-5), taking on the third seed, East Rockaway (14-4), at Farmingdale State College at 10:30 a.m. Saturday and Sunday. In baseball, No. 1 seed Wantagh (19-3) travels to No. 2 seed Wheatley (18-3-1) for Game 2 of the semifinals Friday at 4:30 p.m.