Weston, the No. 1 seed, scored four runs in the fourth inning to stay ahead for good.
Asher Lee-Tyson had two hits for Weston and scored two runs. He also pitched a complete game, striking out six and walking three.
Ethan Lee-Tyson had three hits and scored a run and Jared Weisman drove in three runs.
Weston will now play in the semifinals on Tuesday at Bethel High at 7 p.m.