CHAPEL HILL — Marcus Paige, the North Carolina freshman point guard, hadn’t scored more than eight points in any of the Tar Heels’ previous five games. He scored that many in overtime on Saturday to help lead the Heels to a 72-60 victory against Virginia Tech. The 12-point margin was hardly indicative of the struggle UNC (15-6, 5-3) faced much of the game. The Hokies (11-10, 2-6) began the game on a 12-0 run, and the Heels trailed by six, 32-26, at halftime. But UNC continued to whittle away Virginia Tech’s lead, and the teams went into overtime tied at 55.