GREENSBORO— In a brutally physical game that featured 48 fouls and 57 free throws, the least intimidating presence on the court made the biggest difference.

Duke sophomore Mike Dunleavy, all 6-foot-8, 204 pounds of him, tied a career best with 21 points and converted a layup and 3-pointer in the closing minutes of Tuesday night’s 78-77 win over Illinois. Dunleavy’s back-to-back baskets stretched the Duke lead to nine points and gave the No. 1 BlueDevils enough of a cushion to top the ninth-ranked Illini in the marquee matchup of the ACC-Big TenChallenge.

“That was just being in the right place at the right time and hitting the shots,” Dunleavy said. “At the beginning of the second half I hit a couple of shots and that got me into the game.”

Duke head coach Mike Krzyzewski said Dunleavy’s performance was his best of the year, and the Blue Devils needed every bit of it and more. Point guard JasonWilliams also tied a career best with 23 points, connecting on 7-of-9 free throws.Duke’s bruiser, Carlos Boozer, added 12 second-half points and missed just one freebie in the final 20 minutes to finish with 15 points.

TheIllini, despite 26 turnovers, had a chance to win or tie in the closing seconds after Jason Williams fouled Illinois point guard Frank Williams on a 3-pointer with 3.5 seconds to play. Frank Williams swished the first two — then banked home the one he tried to miss on purpose. It was Illinois’ final shot of the game and sent the primarily pro-Duke crowd of 17,966 home from the Greensboro Coliseum in a happy mood.

“It was one of those nights,”Illini head coach Bill Self said. “He throws a brick up there and somehow it goes in.”

Illinois (4-2) faced the No. 1 team in the nation for the second time in a week. The Illini fell 79-76 to then-No. 1 Arizona in the championship game of the Maui Invitational. Tuesday night’s loss dropped Illinois to 1-19 all time against a No. 1 in the Associated Press poll.

Duke, meanwhile, improved to 125-18 as the nation’s best team and 6-0 this season. But No. 125 was unlike any other.

“We beat a terrific team tonight in an amazingly physical game. It wasn’t a finesse game,”Krzyzewski said with a laugh. “They’re good, and I thought we played better than them in the second half and that’s why we won.”

Krzyzewski stormed off the court at halftime with Illinois holding a 35-34 lead thanks to an intentional elbow from Blue Devil Casey Sanders and the ensuing Illini free throws. Duke had plenty to talk about at the break: Illinois owned a whopping 24-10 edge on the boards and had held Duke to 40-percent shooting from the field, including a 3-for-12 effort from the 3-point arc.

“That’s what we live off of with this team. We’re a smash-mouth team,”McClain said. “That was our goal, to go out there and kill them on the boards.”

The physical play intensified in the second half as the 6-4, 230-pound McClain, 6-9, 235-pound Marcus Griffin and 6-11, 250-pound Robert Archibald continued throwing their weight around. This time, though, whistles blew more frequently.

Ten fouls, five on each team, were called within the first four minutes of the final half, which began to take a toll on the Illini’s inside game.

“Illinois did a great job running their half-court sets,”Jason Williams said. “They have such a good inside game. They’re just really deep and powerful and strong. They tried to bully us, and sometimes it worked.”

As the Illini power game faded to the bench, Duke heated up from the perimeter. Dunleavy hit three straight shots to give Duke a 47-44 lead with 15:36 to go, and Jason Williams sparked a 9-0 run that had Duke in front 57-50.

Six straight free throws and a Sean Harrington 3-pointer put Illinois back on top at 61-60 with eight minutes remaining before Duke finally found an opening.

Brian Cook missed a pair of free throws that left Duke leading by three points. Two Illini turnovers followed, the first of which led to Dunleavy’s layup off an inbounds play. Jason Williams then foundDunleavy for an open 3 after the second turnover and Duke led 77-68 at the 2:33 mark.

“We knew coming into this ballgame we were going to have to protect the ball,”Frank Williams said. “Cory (Bradford) and I combined, we just turned the ball over way too much. We’re supposed to be one of the top backcourts, we’re supposed to have a little more control than that.”

Bradford, who struggled with 13 points on 4-for-10 shooting, hit a 3-pointer and two Duke turnovers — the Devils finished with just 12 — set up Frank Williams’ three-point play in the closing seconds. But after the final free throw banked home, Duke inbounded the ball and left Illinois with eight-10ths of a second showing on the clock.

“That was a great college basketball game to be in November,” Self said. “I don’t know how Coach Krzyzewski would feel, but the game went exactly as scripted. It was their speed against us trying to make it a street fight inside.

“When we were able to get the ball inside, good things happened. When we weren’t, it was because we were turning it over and they were laying it up.”