Plumlee scored 20 points and grabbed a career high-matching 17 rebounds to lead No. 5 Duke to an 89-71 victory over Minnesota on Thursday in the opening round of the Battle 4 Atlantis.
The 6-foot-10 senior had four solid games this season before putting on an impressive performance against a team known for being physical and playing defense.
"Maturity is what you need to be this good," Krzyzewski said. "Most kids don't figure that out. He has. And it wasn't a case of him being immature before, he has just matured."
Seth Curry scored 25 points for Duke (4-0), which will face the winner of the first-round game between No. 19 Memphis and VCU in Friday's semifinals.
Plumlee was coming off a career-high 28 points on 9-for-11 shooting from the field, 10 of 11 from the free throw line and had nine rebounds in the Blue Devils' previous game, an 88-67 win over Florida Gulf Coast.
He was 8 of 10 from the free throw after coming in 17 of 22 (77.3 percent). That is very impressive for a guy who shot 52.8 percent from the line last season and 54.3 percent and 44.1 percent the two seasons before.
"I'm in a role that I love and feel like I am in control and confident in myself and my team," Plumlee said. "I think guys like Quinn (Cook) stepping up playing great and Ryan (Kelly) is playing better too. I think everything is heading in the right direction."
Sophomore point guard Quinn Cook had a career-high 17 points for the Blue Devils who extended their regular-season tournament winning streak to 21 games, a run that stretches to the championship game of the 2006 CBE Classic.
"My job is to communicate with everybody and be a leader," Cook said. "My teammates have confidence in me and know I can do what I have to when things break down."
"We're not going to score that much from our bench, that's not what those guys have to do when they get in the game," Krzyzewski said. "It doesn't always have to be a certain way. These guys come in to make the hustle plays, rebound, defend. Do what we need to be done."
Rodney Williams had 16 points for the Golden Gophers (4-1), who just couldn't cut into the Blue Devils' lead in the second half.
"I think we had a couple of lapses on defense," Williams said. "Duke hit some big shots in the second half when we were playing good defense."
Duke's lead ranged from 10 to 13 points throughout most of the second half. Minnesota, a team known for its toughness and defense, met its match in the Blue Devils, who were just as physical as the Gophers, and were more so through the last 5 minutes when Duke pulled away.
"K's teams are always hard to play and that means they are hard to beat," Minnesota coach Tubby Smith said. "Plumlee is really good."
Curry was 8 of 11 from the field and Duke finished 30 of 55 (54.5 percent). Curry made all three of his 3-point attempts and the Blue Devils were 8 of 10 from beyond the arc.
Minnesota had held its first three opponents to 28.6 shooting from the field and 19.1 percent on 3s while giving up 48.0 points per game.
Obviously Duke was a little bit better than the Gophers' first three opponents.
"We felt we could try and get physical with our three big guys but he's just a real talented player," Smith said. "Game plans are meant to work but it didn't today."
This was Duke's 150th consecutive game ranked in the Top Ten and the Blue Devils are 150-30 in those games.