Grayson Allen's game-high 23 points were not enough to overcome the Cardinals as the Blue Devils fall to 2-3 in ACC play. (0:46)

LOUISVILLE, Ky. –- Grayson Allen arrived at the KFC Yum! Center as college basketball’s resident villain. The Louisville student section came ready to police every wayward move of his limbs and to boo him from opening tip to final horn.

The Allen drama never really materialized. There was no tripping. No conniptions. Unfortunately for the Blue Devils, there was one big Egyptian.

Of all the possible storylines for this early-season ACC crossroads game, the idea of Anas Mahmoud finishing as Louisville’s most potent offensive weapon would likely have hovered in the bottom five percentile. But Mahmoud’s career-best 17 points and 11 rebounds not only smoothed the path toward the No. 14 Cardinals’ 78-69 victory, it exposed some glaring Duke issues in a season stuffed full of them.

The latest problem to bedevil the Blue Devils was a lack of depth and experience inside. Their best big man, senior Amile Jefferson, missed his second straight game with a bone bruise in his right foot. Even without Jefferson, Duke had three McDonald’s All-Americans and two projected NBA lottery picks in its frontcourt with freshmen Harry Giles, Jayson Tatum and Marques Bolden.

Yet that trio – and throw in forwards Javin DeLaurier and Chase Jeter for good measure – combined to score only one more point than Mahmoud. The same 7-foot Mahmoud who grew up in Cairo, weighed 184 pounds in high school and barely cracked the ESPN 100 list (No. 99) during his senior year.

He admitted he had a little extra motivation going up against Duke’s celebrated freshman class.

“It does fire me up,” said the junior, who recorded his first career double-double. “We want to go out there and prove to everybody that we’re not less than anybody. We can beat anybody when we play great team basketball. We showed that today.”

Louisville junior 7-footer Anas Mahmoud, averaging 5.8 points per game, had a big day against Jayson Tatum and Duke's young frontcourt with a career-high 17 points to go with 11 rebounds. Jamie Rhodes/USA Today Sports

Duke looked like a possible super team coming into the season, the overwhelming No. 1 in the preseason poll. That presupposed that Giles, Tatum and Bolden would be great from the get-go. They showed Saturday that they need more time to develop.

Tatum went just 3-for-11 from the floor, and Louisville continually drove right at him on defense. Giles, coming off two knee surgeries, lumbered down the floor early and didn’t score in the first half, though he showed more burst in the final minutes with a couple of dunks.

“It’s not going to be a game or two or three,” Giles said. “It takes time, especially with a knee. It’s going to be a long process, getting used to the physicality, the speed of the game.”

Bolden played only five minutes and didn’t score or grab a rebound. Giles’ three offensive rebounds were the only ones the Duke frontcourt managed all game.

Meanwhile, Duke's interior defense fell to shreds without Jefferson’s on-court leadership. Mahmoud had four open layups in the first half and got fouled on another. In the second half, when Duke desperately needed a stop, Bolden found himself way out of position after Ray Spalding caught a pass in the lane. Spalding, despite giving up 30 pounds to Bolden, easily drove into the freshman’s chest for a three-point play.

Those kinds of breakdowns happened repeatedly, as Louisville scored 36 points in the paint and shot 65 percent on two-point attempts in the second half.

“All I had to do was set the screen and roll to the rim,” Mahmoud said. “That’s execution. That’s team bonding. We know where everybody is, where we’re going to be and how everybody plays.”

Outside of its backcourt, Duke clearly lacks that cohesion right now.

Allen had drawn all the attention lately for his tripping incidents, which began last year when he flailed at Spalding from the floor in Durham. Louisville students yelled “Sweep the leg!” every time Allen went to the free-throw line, and fans also harassed him with signs and taunts.

But there wasn’t much to criticize Allen for in this one. Donovan Mitchell fell at one point when his feet inadvertently got tied up with Allen’s on a fast break, and later Mitchell hit Allen in the nose in a scrum for a loose ball.

Mitchell said the nose collision was “just in the heat of the moment” and that the two talked briefly after the game.

“Everybody kind of blows his stuff out of proportion,” Mitchell said. “He’s a good kid. He just plays the game with such passion and such energy, it gets taken as dirty.”

Allen had been more of a distributor since his one-game suspension, but he aggressively looked to score against Louisville. He finished with 23 points, his most since a 34-point showing Dec. 10 against UNLV, and nine rebounds. He also had six turnovers, however, again raising questions over whether he’s best suited to play point guard.

A more pressing query: Who else is going to score besides Allen and Luke Kennard, who finished with 17 points but only one-second half field goal? Jefferson’s return date is uncertain, interim head coach Jeff Capel said.

The freshmen need to play up to their potential.

“It’s going to come for them,” Allen said. “They’re in a very tough spot right now because they’re coming into ACC play where they don’t have that much experience because of injuries. They were not even able to practice that much.

“So it’s a tough adjustment for them to get thrown right into it, but they’re learning quickly. I have full confidence in them that they’re going to be great. It’s just a matter of putting things together.”

It’s only Jan. 14, so there’s plenty of time for Duke to figure things out. But the Blue Devils just lost their third straight conference road game and now face a steep climb in the daily minefield that is the ACC schedule. And there's no public return date on coach Mike Krzyzewski's comeback after back surgery.

As Saturday’s loss showed, issues keep popping up even when others calm down. It's starting to feel like it's getting late early, to paraphrase Yogi Berra.

"We have to change this -- period," Capel said. " We have to change it, and that has to be our attitude going in."