Chris Morrow and substitute Matthew Snoddy scored the goals which secured Crusaders' passage into the Irish Cup semi-finals at Ballycastle Road.
Michael Doherty saved from Timmy Adamson, David Rainey and Stuart Dallas in the first half while Sean O'Neill denied Coleraine's Aaron Boyd.
Morrow stooped to head home the opener in the 36th minute and then Doherty tipped over from Jordan Owens.
Snoddy slotted home in added time after Adamson broke clear and set him up.
The Crues will face Donegal Celtic or Dungannon Swifts in the semi-finals.