The Pilgrims suffered a 5-2 defeat at the hands of Chesterfield.
Following two earlier victories over the Spireites this season, United were unable to make it a hat-trick – despite first half goals from Sheriff and Armond.
Boston (3-4-2-1): Charlie Wilkinson; Taylor Jaine, Owen Sheriff, Ben Robson; Logan Tate, Joe Melson, Mackenzie Burdass, Zane Millar; Finlay Armond, Ben Johnson; Elliot Foster. Subs (used): Sam Harris, Han Stevens; (unused): Haydn Tear, Krisztian Gagyi, Oliver Ford (gk).