In the semi-final tie played at Chasetown’s Scholars Ground, the Pilgrims were unable to match their high-flying Football League opponents.
Will Shorrock and Brendan Pooni both scored twice for Neil Woods’ side, while Maziar Kouhyar and Nathan Owen were also on target.
Boston (4-4-2): Harry Payne; James Gordon, Kofi Ross, Bailey Forth, Oli Drummond; Peter Evison (George Hobbins 50), Jack Dykes, Harry Vince, Scott Floyd (Jordan Tate 66); Kemal Yenibertiz, Tinashe Chavundura.