Michael Burbank scored on a free kick and Declan Fitzgerald on a penalty kick as the Hawks (10-2) blanked the Tigers (2-11) in South Berwick.
James Melino and Milo Closson added goals for Marshwood, which also scored on an own goal.
Andrew Perry stopped five shots to earn the shutout.
MARSHWOOD 5, BIDDEFORD 0
Ames, Zachary Arsenault, Liam Donovan, Jackson Drake, Adrian Emerson, Dillon Gassab, Mustafa House, Max Kissaka, Adao McLaughlin, Nathaniel Mpemba, Willy Norman, Kyle Nzombo, Gervasio Pelletier, Dylan Pineau, Xavier Rankin, Benjamin Saad, Huseen Saiwan, Abddullah Scott, Lucas Siku, Miradi Sumbu, Consolation Tremblay, Koby Tshiamala, Presence Withem, Donavin Wood, Jackson
Alley, Liam Anderson, Jack Bailey, James Boisvert, Rogan Boyer, Owen Bynum, Jacob Casey, Ronan Chamberlain, Reid Constantakos, Landon Gagnon, Braeden Hamilton, Jackson Lavin, Brevan Layton, Andrew Maguire, Quinn McCormack, Brandon Melino, James Nelson, Luke Page, Harrison Piazza, Anthony Quater, Noah Sawyer, Joshua Shaw, Carter Starkey, Douglass Waddell, Ethan Yager, Colin