First things first, Duke is having a “down” year.  Coming into the game at Chapel Hill, the Blue Devils were only 19-6 and ranked just 20^th in the nation.  Coach Mike Krzyzewski has found himself with a very limited bench to say the least.  The Blue Devils normally have a six-man rotation, a very slim number for a big time college basketball program.  Just a mere nine minutes into the game, guard Matt Jones landed awkwardly on his ankle and was forced to leave the game and not return.  Duke, who was already without forward Amile Jefferson, now was left undermanned on the road against the fifth-ranked team in the nation and their arch nemesis, North Carolina.  North Carolina’s post players dominated the Blue Devils all game long.  UNC’s Brice Johnson ended with a game high 29 points and 19 rebounds, and Justin Jackson added 13 and 8, respectively.  The game seemed to swing in North Carolina’s favor when Duke’s center Marshall Plumlee picked up his fourth foul early in the second half, leaving Coach K to insert freshman Chase Jeter into the game.  Jeter hasn’t played much all year and the Blue Devils needed Plumlee on the floor badly.  Plumlee reentered with ten minutes to play with four fouls and refrained from picking up his fifth for the remainder of the game.  Duke’s Grayson Allen, the hero from last year’s National Championship game, and freshman Brandon Ingram kept the visitors in the game each time North Carolina seemed on the way to putting the game out of reach.  Allen had a team high 23 points, and Ingram added a double-double with 20 points and 10 rebounds.  Luke Kennard replaced injured Matt Jones for the Blue Devils and chipped in 15 points of his own as he proved to be the game’s real x-factor.  North Carolina’s poor three-point shooting allowed Duke to overcome the Tar Heels’ advantage inside.  Somehow, the Blue Devils were able to escape Chapel Hill with their twentieth win of the season and a momentous win over rival North Carolina.