CHARLOTTE, N.C. » Duke’s youngsters saw plenty in their first NCAA Tournament game: the buzz of a fast start to a big lead, the challenge of putting away an overmatched opponent that keeps playing hard, even an irate Hall of Fame coach.

Quinn Cook scored 22 points to help the No. 1-seeded Blue Devils get off to a torrid start and beat Robert Morris 85-56 on Friday.

Jahlil Okafor added 21 as the Blue Devils (30-4) wasted little time getting their offense revving, hitting their first seven shots and 12 of 15. Duke led by double figures from there, with the night mostly about learning how to play in March for a team with four freshmen among its eight scholarship players.

"We’ve played in some big-time games and earned a spot here in the NCAA Tournament," said Cook, a senior. "I just told them to be themselves."

That’s not to say everything went perfectly.

Okafor blew a reverse dunk in the second half, prompting coach Mike Krzyzewski to spring up and point to junior reserve Marshall Plumlee to replace his star freshman big man. He burned a timeout at the 14:53 mark, and then animatedly addressed his team from the edge of his chair in the huddle.

"I know them well enough: I feel like I can get emotional, funny, serious, and they’ll respond because of the relationships that have been built," Krzyzewski said. "And it’s my responsibility to spontaneously act when I do have a feel, when I do see something and for them to react to me. And they’ve done that."

Robert Morris — the No. 16 seed that had to win a First Four game to get here — showed plenty of fight and kept hanging around for the first part of the second half. The Colonials (20-15) twice pulled within 10, but the Blue Devils put the game out of reach with a suddenly dominant 12-0 burst — started by freshman Justise Winslow — that pushed the lead back to 68-46 on Amile Jefferson’s layup with 8:29 left.

"Coach is intense," Jefferson said. "His passion is at a high level and guys aren’t afraid of that. When Coach let it out, guys responded."

Duke was in command from there for a routine 1-vs-16 finish, shooting 63 percent in the program’s 100th NCAA Tournament victory.

Duke will play No. 8 seed San Diego State on Sunday in the round of 32 of the South Region. The Blue Devils are a No. 1 seed for the 11th time in 18 seasons, but first since 2011.

More importantly, Duke got off to a good start in the tournament after a pair of shocking one-and-done exits in the previous three seasons, both in its home state of North Carolina. Last year, the Blue Devils lost to No. 14 seed Mercer in Raleigh, roughly 30 minutes from Duke’s campus.

Rodney Pryor scored 23 points on 10-for-19 shooting for Robert Morris, the Northeast Conference champions who were in their eighth NCAA Tournament.

"They’re a terrific team obviously, and made the night uncomfortable for us," Colonials coach Andrew Toole said. "I would have liked to have made a couple more shots or been a little more poised offensively at times, but I thought we competed the way we wanted to compete."

TIP-INS

Robert Morris: Marcquise Reed scored 22 points. … Lucky Jones managed a personal first-half highlight, dropping down in the paint to swat away Okafor’s layup. … Robert Morris shot 36 percent.

Duke: Cook hit six 3-pointers. … Okafor went 9 for 11 in 21 minutes. … Duke improved to 33-6 in its home state in the NCAAs and 46-9 as a No. 1 seed. … The Blue Devils made 10 of 21 3-pointers.

WINSLOW’S SPARK

Winslow started Duke’s putaway run with a 3-pointer, and then took a rebound for a layup and assisted on Tyus Jones’ 3. He finished with six points and 11 rebounds.

REGROUPING

The Colonials regrouped from Duke’s opening flurry and ran off a 10-0 run to get to 54-44 on Pryor’s layup with 12:26 left, seizing a glimmer of hope for their boisterous fans.

"Hats off to our team for pushing and still staying with it, still having the courage to fight back and make the simple plays and the right plays," Lucky Jones said.

UP NEXT

Robert Morris’ season is over.

Duke will play San Diego State on Sunday.