The Pilgrims defeated Scunthorpe United 4-2 at The Jakemans Stadium courtesy of Clare's fifth minute header, Rollins' fine angled strike in the 10th minute and Thewlis' bullet two minutes before the break.
George Green added a fine fourth in the 70th minute, with John McAtee on target for the Iron towards the end of both halves.
Boston (4-3-3): Peter Crook (George Willis 46); Ben Middleton (Arlen Birch 56), Luke Shiels, Simon Ainge (Chris Robertson 68), Ashley Jackson (Alex Whittle 72); Brad Abbott (George Green 56), Andi Thanoj, Tom Platt (Jonathan Wafula 72); Jay Rollins, Tom Clare (Shaun Tuton 46), Jordan Thewlis.
Scunthorpe (4-4-2): Adam Kelsey; James Horsfield, Joseph Cummings, Jai Rowe, Lewis Butroid; Omar Sanyang (Mason O'Malley 7), George Hornshaw, John McAtee, Lucas Sinclair; Kevin Van Veen (Harry Jessop 75), Jordan Hallam (Tom Pugh 71). Subs (not used): Reon Potts, Charlie Barks, Harry Baker, Tom Collins (gk).
Referee: Martin Chester.
Attendance: 442 (30 visitors).