Rovers equalised on 61 minutes, Matt Taylor heading his 12th goal of the season unmarked on the six-yard line from Dan Leadbitter's right-wing cross.
The winner came when Montano found time and space inside the box to shoot home from 12 yards, his shot taking a deflection to wrong-foot goalkeeper Chris Neal.
Fleetwood's livewire strikers Hunter and Chris Long caused Rovers plenty of problems in the first half and both had efforts saved by Roos.
At the other end Taylor forced three saves from Neal and had another effort deflected over as both teams built some penetrating attacks.
Overall, Rovers edged an entertaining clash and just about deserved the points.