The Imps' shadow squad were victorious over the Pilgrims at Riseholme College, on a difficult day for the away side.
United conceded four times before half-time – and a further five times in the second half.
Boston: Sam Buckland (Tyler Griffin 70), Archie Bradford, Alex Van-Tam, Kye Rook (Denis Matei 46), Reece Coy, Elod Nadasdi (Jack Dixon 55), Aron Ealham, Toby Foreman (Cody Elgie 46), Freddie Shinn, Josh Panton, Lake Taylor-Peak (Sam Finch 46).
Referee: Finn Ford.