The Pilgrims' National League U19 Alliance Division F side journeyed to Moulton College to tackle Diamonds.
A solitary goal sealed a 1-0 reversal for the side managed by Brad Easey and Paul Alexander.
Boston: Alfie Harney, Harry Gunthorpe, Alex Van-Tam, Charles Doble, Joel Smith (Jack Dixon 13), Daniel Fisk, Toby Foreman (Daniils Spicins 55), Kye Rook, Finley McDaid, Kiaran Grove (Lake Taylor-Peak 55), Joe Todd (Jaydon Sargent 65).
Referee: Mark Wetherall.