The last Eastern Counties League side went out of the F.A. Cup after this replay.
Tyron Sealey netted the first goal after 111 seconds to deflate their opponents, although Haverhill held out until the hour mark when substitute Mark Ducket slid in to net from close range after Shane Hill's low ball across from the right.
The third came in controversial circumstances ten minutes later, Wayne Mills putting the ball across for Carl Williams to score after he was in an offside position during the build up.
It was 4-0 on 75 minutes, Ducket scoring his second, Shane Hill scoring from the penalty spot on 90 minutes after Jason James was adjudged to have been fouled in the area by Marc Abbott.
ROVERS : Arron Benstead, Dan Pilcher, Ryan Holder, Andy Palazon, Colin Vowden, Joe Harvey, Marc Abbott, Marcus Hunt, Adam Ben-Saud, Richard Heller, Wayne Goddard.
Subs - Adam Salmons (for Joe Harvey, 64), Paul Stokes (for Wayne Goddard, 65), Ben Cowling (for Richard Heller, 80), Louie Farrington, Sam Green.
Goals - None.
Bookings - Dan Pilcher (89, foul).
Red cards - None.
HITCHIN : Ricky Perks, David Deeney, Nick Mountford, Ryan Frater, Lance Gentle-King, Jason James, Tyron Sealey, Shane Hill, Richard Pringle, Carl Williams, Wayne Mills.
Subs - Matt Chilas, Mark Ducket (for Richard Pringle, 58), Nat Gentle-King (for Jason James, 79), Leon Simpson (for Carl Williams, 79), Martin Bennett.
Goals - Tyron Sealey (2), Mark Ducket (60, 75), Carl Williams (70), Shane Hill (90, penalty).
Bookings - Ryan Frater (40, foul), Nick Mountford (72, foul).
Red cards - None.