Red Sox prospect Argenis Diaz hit a two-run triple and scored in a four-run seventh inning that put the Sharks (17-19) on top for good. He also plated a run with a groundout in the fifth for his first multi-RBI game since Oct. 14, also against Waikiki (18-19).
Diaz, who batted .279 with two homers and 40 RBIs in 99 games for Class A Greenville over the summer, is second in HWB with a .359 average, despite struggling through a 5-for-31 slump.
The winner of Sunday's regular-season finale will face the North Shore Honu on Monday in the Championship Game.
Austin Jackson (Yankees) went 2-for-3 with two RBIs and two runs scored, while Fuminori Yokogawa singled, walked and scored twice for the Sharks.
Reliever Ryan Ouellette (1-1), an Orioles farmhand, struck out one in a perfect seventh to get the win. Katsuyuki Aihara fanned Rockies prospect Michael McKenry, the only batter he faced, for his first save.
Sharks starter Jimmy James (Red Sox) yielded two unearned runs on three hits and five walks with six strikeouts over 3 2/3 innings.
Jermaine Mitchell (Athletics) went 2-for-3 with an RBI and two runs scored for the BeachBoys, who also got two hits and an RBI from Jeff Kindel. Fellow Rockies prospect Cole Garner singled twice and scored twice, while Hector Pellot (Mets) singled in the third to extend his hitting streak to 10 games.
Reliever Brant Rustich (3-1), a Mets Minor Leaguer, gave up three runs on a hit and a walk with one strikeout over 1 2/3 innings. Starter Jared Lansford (Athletics) went four frames and was charged with four runs on five hits and a walk while fanning four.
Michael Blinn is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.