Diamond DeShields, the daughter of former major leaguer Delino Deshields, added 17 points and Xylina McDaniel, the daughter of ex-NBA standout Xavier McDaniel, had 14 for the Tar Heels (10-2), who have won five straight.The Gamecocks (9-1) cut a 13-point lead to 55-53 with 9:21 to go on Aleighsa Welch's two foul shots. But McDaniel answered with a driving basket and Muvanga added a putback to extend the Tar Heels lead.South Carolina would not get closer than three points the final eight minutes.Welch led the Gamecocks with a career-high 23 points.North Carolina improved to 26-5 all-time in its annual holiday visit to Myrtle Beach since first playing here in the 1994-95 season.Tiffany Mitchell had 18 points and Elem Ibiam had 14 for the Gamecocks, who were trying to match their best start ever under coach Dawn Staley at 10-0.South Carolina had largely cruised to its undefeated run coming in with a strong offensive showing. The Gamecocks had averaged just under 80 points a game â?? their closest score so far was a 70-50 victory over Southern Cal last month.But Staley said her team hadn't really been tested defensively and her fears were borne out in the opening half as the Tar Heels frequently beat South Carolina down court for easy buckets or found open players on the wing for uncontested jumpers.Mavunga and Gray were a combined 7 of 12 in the first 20 minutes as North Carolina opened up a double-digit advantage.Mavunga's inside basket with 11:30 left put the Tar Heels up for good, 13-12.South Carolina cut it to 23-21 on Ibiam's basket four minutes later before the Tar Heels finished the half on a 16-6 surge. DeShields had five points and Gray four in the run.South Carolina struggled to keep up with the Tar Heels, who defeated New Orleans 124-41 in a game at the convention center on Monday night.The Tar Heels continued to play without the coach who began the holiday tradition in Sylvia Hatchell, who is being treated for leukemia. Team spokesman Mark Kimmel says Hatchell remains in regular contact with longtime assistant Andrew Calder, who's leading the team in Hatchell's absence. The team regularly tapes practice, Kimmel said, with Hatchell breaking it down and adding her input.Hatchell has said she's feeling better and is hopeful to make a return to the bench before the end of the season.South Carolina's coaches and staff joined their North Carolina counterparts in wearing orange ribbons to support Hatchell's fight against the disease.