The Pilgrims booked a third round berth following their 2-1 win over Harrogate Town at RAF College Cranwell on Friday afternoon.
Harrogate led on 22 minutes, but Sanders equalised 12 minutes later and struck the winner with only two minutes to play.
Boston (3-5-2): Sam Vince; Niall Delahoy, Charlie Melville, Lewis Sturman; Leon Squire, Aaron Eyett, Keiron Elliott (Juris Kormis 50), Lewis McKue, George Stainfield (Jordan Sowerby 46); Charley Sanders, Jordan Nuttell. Subs (not used): Karolis Andriulionis, Tom Benton (gk).