The Iron surged into a 3-0 lead, with the Pilgrims only responding briefly through Lenell John-Lewis' close-range effort three minutes from time.

Dan Batty's deflected 12th minute free-kick handed Andy Butler's side an early lead, which was doubled on the stroke of half-time by ex-Pilgrim James Gale. Victory was confirmed by fellow ex-Pilgrim Jean Belehouan in the 69th minute.

United boss Paul Hurst had recalled Terrell Agyemang ahead of kick-off, with Levi Sutton through a groin problem.

The Iron took the lead when BATTY sized up a 25-yard free-kick which took a significant deflection and left Louis Chadwick wrong-footed.

Nine minutes later, James Norwood slammed home Joe Starbuck's cross from the right, only for the offside flag to save the hosts' blushes.

Chadwick made an excellent save to deny Belehouan four minutes before the break, but Boston's respite was short-lived with GALE crashing home the Iron's second in the 45th minute.

Visiting keeper Maison Campbell made a big save in the first minute of the second half to deny Agyemang - and it provided the eventual platform for BELEHOUAN to slam home Scunthorpe's third with 21 minutes to play and secure their safe passage.

Campbell made a good save to deny West Bromwich Albion loanee Ollie Bostock and although JOHN-LEWIS converted from close-range with three minutes to play, the Iron held on, despite Jake Rooney planting a free header narrowly wide at the death.

Boston (4-4-1-1): Louis Chadwick; Connor Teale, Jake Rooney, Niall Canavan, Lewis Shipley; Ollie Bostock, Nicholas Pozo, Terrell Agyemang, Georgie Gent (Ken Aboh 46); Connor McBride (Lenell John-Lewis 46); Tom Cursons (Lennon Wheeldon 76). Subs (not used): Jack Holmes, Ben Hammond, Jamie Grimes, Luke Faxon (gk).

Scunthorpe (3-5-2): Maison Campbell; Will Evans, Jean Belehouan, Stan Ashbee; Joe Starbuck, Jordan Richards (Jacob Butterfield 72), Dan Batty (Luke Brennan 84), Kyle Hurst (Tyrell Sellars-Fleming 76), Tyler Denton; James Norwood (Ross Barrows 90), James Gale (Pat Jones 55). Subs (not used): Regan Clayton, Louis Jones (gk).

Referee: Darren Drysdale.

Attendance: 1,708 (395 visitors).

PIC: Chris Bray.