As he walked onto the wrestling mat for his championship bout inside Southern Regional High School’s gymnasium on Feb. 16, Griffin Jackstadt was as surprised as anybody.

“After I won my semifinal match, it hit me hard,” said the junior heavyweight from Barnegat. “I said to myself, ‘Holy crap. I can do this.’ I realized I could go out there and win a championship, that it was possible.”

Facing fourth-seeded Elijah Wilson of Highland Regional in the 285-pound final, the second-seeded Jackstadt scored a…