The depleted Pilgrims, without a recognised goalkeeper and their Boston Grammar School contingent, were beaten 4-1 at Chasetown.
Kyle Tate deputised between the sticks as United put up a brave showing in Staffordshire.
Boston (4-3-3): Kyle Tate; Jamie Gaukroger, Harry Cranfield, Lewis Bontoft, Nathan Stevens; Marc Tucker (Ethan Thorpe 60), Marshall Young, Elliott Ramsden; Xander Crashley, Harrison Holland, Will Jackson. Sub (not used): Brendan Oldham.