Duke aims to finish nonconference play with an unblemished record when it visits Middle Tennessee State for a Saturday afternoon clash in Murfreesboro, Tenn.The Blue Devils (3-0) also eye their second consecutive 4-0 start and momentum heading into a Sept. 28 tilt against rival North Carolina in their Atlantic Coast Conference opener.But first up are the Blue Raiders (1-2), who, like Duke, are led by a first-year head coach.Despite this being the second head coaching stints for both Middle Tennessee’s Derek Mason and Duke’s Manny Diaz, they have never faced each other from opposing sidelines. Diaz was an assistant at Middle Tennessee nearly two decades ago, serving as the defensive coordinator there from 2006-09.While Duke is coming off its third straight win after a 26-21 victory over UConn last weekend, MTSU hopes to bounce back from a 49-21 loss to Western Kentucky that Mason put on himself and no one else.”At the end of the day, I don’t blame players, I blame me,” Mason said. “My shoulders are big enough. What we will do as a staff and as a team is hold each other accountable. Because that’s where the winning gets done.”Middle Tennessee’s issues have shown up on defense, where it ranks 129th out of 133 FBS teams with 42 points allowed per game. Even in its lone win against FCS side Tennessee Tech, the Blue Raiders allowed 25 points.Duke hasn’t had a problem finding the end zone, especially in crucial moments. Each of the Blue Devils’ past two wins — against UConn at home and on the road against Northwestern — required late-game comebacks.