It seems to happen every year at Duke: The Blue Devils get rolling again after a January lull.
    Back in the national rankings after a two-week absence, Duke looks like its heating up again.
    No. 20 Duke (19-6, 8-4 Atlantic Coast Conference) has reeled off four straight wins — with the last two coming against top-15 teams — and enters this week's rivalry game against No. 5 North Carolina (21-4, 10-2) with strong momentum.
    The current winning streak — which includes victories over then-No. 13 Louisville and No. 7 Virginia in a six-day span — has pushed that four-losses-in-five-games slump further into the past. It's also provided some tangible evidence that the Blue Devils weren't entirely doomed to disaster without forward Amile Jefferson, who's been sidelined indefinitely with a broken foot.
    "The best way to learn is through experience, and during January, after losing Amile, we had to become a different team and they were learning that — there wasn't a preseason to learn it," coach Mike Krzyzewski said Monday. "You're thinking about what you have to do, and not what we have to do, and as we've gone further ... in conference play, our guys are thinking about what we have to do and making spontaneous corrections, instant corrections, on the court instead of waiting until halftime or the end of the game."
    Those things weren't happening during that 2½-week stretch of mid-January when the Blue Devils lost three straight and four of five to drop out of the Top 25 for the first time since 2007.
    But cold stretches in January are hardly out of character for Duke.
    Last year's team dropped two straight and three of six during the first month of conference play before beginning its run to the program's fifth national title. Each of Duke's previous two teams also dropped two of three at almost the exact same spot in the schedule.
    All of those teams also got rolling before the first of two annually scheduled matchups with the Tar Heels: For the fourth straight year, Duke brings at least a four-game winning streak into that first UNC game.
    "Our sense of urgency these past couple of weeks has been excellent," guard Matt Jones said, "and we need to carry our momentum over to the Dean Dome."
    What's happened is, Duke is finding ways to win the close games. That didn't happen during the January swoon.
    The three losses to Clemson, Notre Dame and Syracuse were decided by a total of 11 points. All were one-possession games in the final moments.
    The winning streak started with a second-half rally to beat Georgia Tech — a game Krzyzewski said he watched from the cardiac ward of Duke University Hospital after he fell ill the night before. The Blue Devils reeled off three straight tense wins at home over North Carolina State, Louisville and Virginia, with comfortable leads slipping away in each before Duke made the plays it needed down the stretch.
    None was bigger, or more polarizing, than the bank shot in the lane by Grayson Allen, who beat the final buzzer against the Cavaliers — but might have gotten away with an extra step in the process.
    "We weren't awful in the games that we lost," Krzyzewski said. "We weren't good enough. And we were a few possessions better in the games that we've won, and so there's been continued improvement. It's not like going from one extreme to another extreme. It's been a gradual process."