Key played at GT under George O'Leary. In fact, Key was on the 1998 Jackets squad that finished 10-2, tied for ACC Champ and Gator Bowl champ. Later Key was an assistant under O'Leary at UCF, including all 4 of O'Leary's double digit win teams at UCF. And then Key was an assistant under Nick Saban.
All that means that he may not be as good as GT can expect to hire, but that he might have it in him to rebuild GT football. But this GT team is not there, not close. UNC should win by 3 scores or more.