Harrison Barnes added 20 points for the Tar Heels (24-4, 11-2 Atlantic Coast Conference), who extended their domination of their nearby rivals. North Carolina has won 12 straight meetings and hasn't lost to the Wolfpack (18-10, 7-6) in five years.
The Tar Heels shot 51 percent, including 10 for 19 from 3-point range. And Marshall was a big reason for that success, whether he was knocking down outside shots against sagging defenders or finding teammates for baskets.
The pass-first point guard came in with just three double-digit scoring games all season, but went 7 for 8 from the field and 4 for 5 from behind the arc to provide an unexpected burst of offense. Marshall also hit all four of his free throws and had no turnovers in 38 minutes.
C.J. Leslie had a career-high 24 points to go with 12 rebounds for N.C. State, while Lorenzo Brown had 18 points. But the Wolfpack just couldn't keep up with the Tar Heels.
Playing in front of a rowdy home crowd, the Wolfpack fought back from an early 14-point deficit in the first half and trailed by just five at halftime. The Tar Heels quickly pushed the margin back to double figures after the break. Then, with the Wolfpack within seven, the Tar Heels ran off nine straight points to take a 71-55 lead on Barnes' jumper over C.J. Williams with 8:18 left.
Marshall followed that with another 3 for the Tar Heels' largest lead at 74-56 with 7 1/2 minutes left -- signaling yet another UNC win in the series.
The Tar Heels had won the past 11 games by an average of nearly 16 points per game. That included the first meeting in Chapel Hill last month, when the Tar Heels dominated the entire way and led by 31 points in the second half of a 74-55 win.
It wasn't quite as easy this time around. Then again, the Tar Heels remained in firm control of this one, turning away several spurts by the Wolfpack and playing from in front almost all night before stretching the lead out in the final 11 minutes.
N.C. State has lost to Duke, Florida State and North Carolina in the past week, the three teams that entered the week leading the ACC standings. This might've been the Wolfpack's last chance for a marquee win to help its NCAA tournament chances.