The Pilgrims entertained high-flying Tamworth on the Jakemans Community Stadium 3G pitch – and suffered a seven-goal defeat.
United were 6-0 down at half-time, but showed a marked improvement after the break, with substitute keeper Tyler Griffin saving a second half spot-kick.
Boston: Joe Douce (Tyler Griffin 59), Alex Van-Tam, Jack Clayton, Charles Doble, Reece Coy, Joel Smith, Harry Gunthorpe, Kye Rook, Matas Gecas (Jake Leggate 79), Cody Elgie (Kiaran Grove 51), Jaydon Sargent (Daniel Walsh 59).
Referee: Istvan Mod.