Updated at 4:55 p.m. CST March 20

CHARLOTTE, N.C. — Sean May and sixth man Marvin Williams bullied North Carolina back to the round of 16, leaving Iowa State’s six-man rotation gasping for air along the way.

May had 24 points and 17 rebounds, Williams finished with a career-high 15 rebounds and the top-seeded Tar Heels beat the Cyclones 92-65 Sunday to advance past the first weekend for the first time in five seasons.

Williams scored 20 points — tying his season high for the second consecutive game — and Rashad McCants added 17 for North Carolina (29-4), which went to the Final Four in 2000 before the tournament drought. Now, coach Roy Williams has the Tar Heels back in the regional semifinals in his second season, the 10th time he’s made it that far in 17 NCAA tournament appearances.

The Tar Heels will face fifth-seeded Villanova next weekend. They also set up a possible matchup with league rival North Carolina State in the final of the Syracuse Regional. The 10th-seeded Wolfpack beat No. 2 seed Connecticut 65-62 Sunday.

This one was pretty easy. Iowa State (19-12) beat Minnesota in the first round with stifling defense, but it was no match for North Carolina’s offensive prowess. Time and again, point guard Raymond Felton penetrated to find open teammates, and if they missed their shot, May or Williams likely was there to clean it up.

During one brilliant stretch of the second half, the duo dominated on both ends of the court to help the Tar Heels pull away. May started it by blocking Curtis Stinson’s layup back out to halfcourt, then took advantage of a nifty pass from Felton on the other end for a layup to make it 48-35.

May rebounded a miss from Iowa State’s Will Blalock, grabbed one by McCants at the other end and put it back before getting his 10th rebound of the game when a hook shot by Iowa State’s Jared Homan bounced off the rim. Second later, when McCants went to the free throw line, Williams replaced May and scored almost immediately, swishing a jumper on a feed from McCants.

After Williams blocked a layup by Blalock, May came back in for Jawad Williams, and he set up a 3-pointer for McCants with a pass and screen to make it a 19-2 run and a 55-35 lead. Cyclones coach Wayne Morgan called a timeout but, at that point, it was futile.

Homan, playing in his final game, finished with 19 points and 20 rebounds, but he had little help. Iowa State got outrebounded 50-47 and had 17 turnovers while shooting only 36 percent to finish its surprising run back to the tournament.

Midway through the first half, freshman Quentin Thomas became the ninth North Carolina player to take the floor when he gave Felton a quick breather. The Cyclones had to rely on six, much as they had all season, and Homan and Stinson each ended up playing 38 minutes.

The margin could have been much larger if the Tar Heels had made their free throws. They were only 22-for-37 (60 percent), but it was more than enough.