The Pilgrims journeyed to the International Stadium to face Gateshead. They trailed 3-0, before rallying strongly after half-time.
Charlie Brooks and Josh Doran scored twice in quick succession – but United could not find a leveller.
Boston: Cameron Fox, Ellis Perry-Burdett (JJ Ward 25), Josh Doran, Charlie Brooks (Lucas Turrell 55), Taylor Jaine, Finley Ging, Rueben Fogg, Kris Zaluzinskis, Luke Horne, Joe Wilkinson, Ezra Aaron.