The Pilgrims chalked up a 2-1 National League U19 Alliance victory over Rugby Town at Butlin Road.
Bastow's fifth minute opener and Crashley's brilliant finish 10 minutes into the second half sealed the deal for Lee Mitchell's side who were missing scores of registered players through injury, suspension and Easter unavailability.
Boston (3-6-1): Jake Frestle; Jamie Gaukroger, Nathan Stevens, Will Jackson; Xander Crashley, Dougie Barrett (Ben Johnson 46), Marshall Young, Craig Forbes, Kyle Tate, Jenson Bark; Jack Bastow.