"We can make shots, we can, and hopefully, they (got) the confidence they needed," Zimmerman said.
The 3-pointer helped to prevent Milton from taking a lead despite pulling within two quick possessions of it in the second half.
"Milton's tough," Zimmerman said. "They have a lot of experience."
On an open look midway through the third quarter, Weaver set his feet and knocked down a three.
Travis Krall, who scored 18 points, answered inside for Milton, but Sebasovich showed his range, draining from beyond the arc to put the Indians ahead, 34-25.
Shamokin established its perimeter game early with Sebasovich hitting a pair of threes in the opening minutes of the game.
Rebounding on the defensive glass and converting at the other end, the Indians scored 11 straight points to extend an 11-10 lead to 12 points before halftime.
Ethan Baker brought his team back, scoring five straight points to end the half.