The Pilgrims twice led through Fogg’s early chip and Sheriff’s penalty – but Blyth hit back to level at 2-2 at half-time.
The visitors struck twice more in the second half to leave the Jakemans Community Stadium 3G with all three points.
Boston (4-3-3): Cameron Fox; Kelton Robinson (Taylor Redman 60), Owen Sheriff, Taylor Jaine, Lucas Stubbs; Rueben Fogg, Han Stevens, Jake Henderson; JJ Ward (Kyle Featherstone 85), Jake Higginbottom, Patrik Bad (Jack Waddington 70). Subs (not used): Oskar Rajski, Mark Williams.
Referee: Alistair Wilson.