The victory advances Sweetwater Valley into an elimination game Tuesday against the team representing Kentucky's Bowling Green Eastern Little League in South Williamsport, Pennsylvania.
Bonita-based Sweetwater Valley defeated Bowling Green Eastern, the Great Lakes Region champion, 14-2, on Friday in a game called in the top of the fourth inning because of the 10-run rule.
Nate Nankil and Walker Lannom had RBI singles preceding Baptista's grand slam as Sweetwater Valley erased a 2-0 deficit.
Nankil hit a two-run homer in the sixth and final inning, followed by Lannom's homer. Dante Schmid homered one out later for Sweetwater Valley's final run.
Caleb Harris homered to lead off the bottom of the first for Cranston Western, the New England Region champion.
David Marchetti, the No. 2 batter in the lineup, singled, moved to second on a wild pitch, advanced to third on an error and scored on Cam Adamec's single.
Marchetti homered in the third.
Levi Mendez pitched a complete game for Sweetwater Valley, striking out 11 and not walking a batter in six innings. He allowed three runs (two earned) and four hits.
Sweetwater Valley, the West Region champion, needs two more victories to advance to Saturday's U.S. championship game. A loss will end Sweetwater Valley's play in the Little League World Series.
Sweetwater Valley was forced into an elimination game because of Sunday's 8-4 loss to the all-star team from Texas' Pearland West Little League, Sweetwater Valley's first loss after winning its first 17 games in five tournaments this summer.