Who says that the college basketball regular season doesn’t matter? (BCS apologist Kirk Herbstreit, that’s who.)

It sure mattered yesterday when the #1 Tar Heels went into Durham and upended the #5 Blue Devils, 76-68. Duke led, 68-66, with three minutes to play, but North Carolina went on a 10-0 run to close the game and seal the win.

It’s always interesting to see how each team deals with the emotion of these matchups. Earlier this season, in Chapel Hill, the Tar Heels seemed anxious and overexcited while Duke, playing on the road, was calm, cool and collected. Last night, the roles were reversed. Duke got off to a bad start and didn’t get settled until the second half.

It was senior night for DeMarcus Nelson, and it felt like he was forcing things all game. He shot just 3-12 from the field. Gerald Henderson also went 3-12 and came up small in the final minutes, blowing a layup that would have put Duke up by four. He had another missed shot and a turnover during UNC’s run. Lastly, freshman Kyle Singler rounded out the bad shooting with a 3-10 effort. The only Duke players to really play well were Jon Scheyer and Greg Paulus.

Danny Green led North Carolina with 18 points, while Tyler Hansbrough and Wayne Ellington each chipped in with 16. Hansbrough also had 15 rebounds.

In recent years, North Carolina’s problem has been mental toughness down the stretch, but they showed it last night in a difficult environment. Getting Ty Lawson back certainly helps, but he isn’t practicing much so that might come back to bite them in the tournament.

UNC has a virtual lock on a #1 seed, and will probably get to play in Charlotte and Raleigh, making them a big favorite to reach the Final Four. Duke needs to win the ACC tournament and hope some of the other top teams lose in order to have a shot at a #1 seed in another region.