Shelby Vaccaro scored the game-winner unassisted with 3:44 left in the second half for No. 3 Bay Shore in its 10-9 win in the Suffolk Class A girls lacrosse semifinals at No. 2 West Islip on Wednesday.
Casey McGowan scored on an assist from Devan Crimi with 4:08 to play to tie it at 9 for West Islip (14-3).
Katie Lawlor made eight saves, including a stop on a free position attempt with 1:10 play for Bay Shore (15-3), which never trailed and led 3-2 at halftime.
The Marauders last made a county final in 2006 and last won it in 2005. They will play No. 1 Northport, the two-time defending Suffolk Class A champion, at 3 p.m. next Wednesday at the Dowling Sports Complex.
Caroline deLyra led the Marauders with a game-high three goals, while Vaccaro and Kyra Harney each added two goals and one assist, and Claire Healy chipped in with two goals.
Stefani Jackson and McGowan each scored two goals for West Islip, and Alyssa Costantino made 11 saves.
West Islip had defeated Bay Shore the last four times these teams have met, including an 11-7 win at the same site in the same round of the playoffs last season.
The Lions held Bay Shore's leading scorer, Northwestern-bound Alyssa Leonard (49, including a season-high seven in a 12-9 quarterfinal win over Middle Country), scoreless. But her teammates picked up the slack, as five different Bay Shore players tallied goals.
In the other semifinal, Shannon Gilroy scored a game-high six goals with one assist, and Allie Breitfeller added four goals and one assist for No. 1 Northport (17-1), which advances to its fifth straight county final. Michaela Aymong made 12 saves, and Paige Bonomi and Kiera McNally each had two goals and one assist. Christina Esposito led No. 4 West Babylon (13-5) with five goals and one assist, and Samantha Rush added three goals and one assist.