Town enjoyed a bright opening, Marco Gabbidini's header was turned over by Royce from close range. Andy Thompson hit over from 12 yards at the other end on 26 minutes.
The home side upped the tempo in the opening minutes of the second half, Paul Rickers denying Danny Shittu with a last gasp tackle before Calum Willock's cross flew across the face of goal.
Town took the lead in the 61st minute through sheer persistance. Jamie Forrester's shot was twice blocked before the ball broke to Trollope on the edge of the area, the Cobblers captain lifted a delightful chip over Royce into the far corner to send the Cobblers fans wild, behind the goal.
Rangers again tried to find away back into the game but they couldn't find a way through the solid claret backline. Even with six minutes of injury time added at the end, The Cobblers held on for a valuable win.
Cobblers Man of the Match
Paul Trollope, lead by example and a brilliant finish.
Ref Watch
Mike Thorpe swung the way of the home crowd and made some terrible decisions.