In their final league fixture before next Tuesday's FA Youth Cup third round clash against Burnley, the much-changed Pilgrims were well-beaten at the Lyme Valley Stadium.
The Pilgrims led after 14 minutes through STURMAN — who netted his third goal of the season.
Newcastle roared back into contention with first half goals after 27 and 34 minutes respectively and effectively killed the contest by netting their third seven minutes after the break.
The triple introduction of Niall Delahoy, Charley Sanders and James Tricks could not spark a United comeback though and Newcastle claimed a deserved victory.
Boston (4-4-2): Marc Hipwell; Scott Langan (Niall Delahoy 55), Lewis Sturman, Jordan Lote, Todd Devlin; Joe Briers, Jake Portas, Jake Beauchamp, Jake Platten (Charley Sanders 55); Jordan Nuttell, Tom James (James Tricks 55).