Ray Power's side slipped to a third successive home defeat – losing 6-1 to the Shaymen.
Hugo Hunt scored United's consolation during the second half to bring the deficit down to 4-1 temporarily.
Boston: Cameron Fox, Ellis Perry-Burdett, Josh Doran, Will Langford (Lucas Turrell 70), Charlie Brooks, Finley Ging (Oliver Fields 46), Nathan Bowen, Kris Zaluzinskis (Joe Wilkinson 76), Jake Henderson (Flynn Slater 46), Rueben Fogg (Hugo Hunt 46), Luke Horne.
Referee: Trevor Basker.