Some say that Duke can't outrebound the big teams. That may be true, but that is not why they will get knocked out. They will get knocked out because they are so worn out.
Coach K, the great coach that he is, does not like to play his bench. He may not have the best, but he doesn't have the worst. That is why Duke loses a lot of close games, because he will keep the starters in for pretty much the whole game.
That is also true when they are down by a lot of points. He will keep them in, and when they catch up with the other team, they are too tired to take the lead.
Duke is in too many close games in the NCAA tournament, and Duke will get tired and lose. Don't get me wrong, I am a big Duke fan. They are my favorite team. But Coach K has got to play his bench some these last few games.