After Duke led by as much as 28 points in the first half, its bench struggled after the break in a 96-80 win against South Dakota Saturday at Cameron Indoor Stadium. Grayson Allen scored 25 points for his highest scoring output since the game against then-No. 2 Michigan State. 

The Blue Zone gives three key takeaways, stats and plays, and looks at the road ahead for the Blue Devils:

Three key takeaways

Can Duke play 40 minutes?

In their last four games, the Blue Devils turned it on in the second half. Against the Coyotes, Duke played an impressive first half, but slowed down with 14 turnovers after the break. The brief stretches of greatness have been enough for the Blue Devils to remain undefeated, but they may not be able to keep winning for long if they can't put two halves together.

Wendell Carter Jr.'s foul trouble is becoming a trend

Carter, a freshman big man, picked up his second foul in the first 11 minutes of Saturday's game and only played 16 minutes all afternoon, scoring six points and finishing with three fouls. Before Saturday, Carter had been whistled for at least four fouls in three straight games, and he has played the fewest minutes by far of any of Duke's starters because of it. Carter is one of the Blue Devils' most fundamentally sound weapons, but he needs to get better at staying on the floor to make the most of his talents.

Starters finally get to rest

After Duke played three straight games within 10 points to cap a stretch of nine games in 20 days, its starters were running on fumes. A commanding first-half lead was just what the doctor ordered, as only one starter played more than 30 minutes and four Blue Devils came off the bench to play at least 14 minutes.

Three key stats

Three points for Matt Mooney

South Dakota's leading scorer was two days removed from scoring 30 points against UMKC and came to Durham averaging more than 18 points per game, but Allen shut him down on defense and held him to just three points. Mooney only took five shots, knocking down one triple a little more than four minutes into the game, and had more turnovers than points. The redshirt junior guard did have five assists, capitalizing on the Blue Devils' emphasis on containing him to generate opportunities for his teammates.

48-24 rebounding advantage

Duke doubled the Coyotes on the boards, as Marvin Bagley III led the way with 12 rebounds in his eighth double-double of the season. The Blue Devils grabbed the offensive rebound on 16 of their 28 missed shots and turned those second chances into 20 points. Duke had four players at least 6-foot-10 each play at least 15 minutes, and that quartet combined for 28 rebounds.

19 turnovers

Duke's 19 giveaways shattered its previous season high of 15 and marked a sloppy second half for the Blue Devils' bench. Sophomore Marques Bolden had six turnovers alone in just 17 minutes, and freshman Alex O'Connell had three. But most of the miscues were dead-ball turnovers caused by traveling violations or bobbled dribbles and passes out of bounds, which limited South Dakota's transition opportunities, and the Coyotes only had 12 points off turnovers.

Three key plays

Allen 3-pointer, 19:19 remaining in the first half

Seconds after South Dakota knocked down a triple to take a 3-2 lead, Trevon Duval took the inbounds pass and quickly kicked it up the floor to Allen on the wing for an open 3-pointer. Allen finished the day 4-of-5 from beyond the arc, and Duke never trailed again.

Bagley dunk, 13:57 remaining in the first half

The most impressive of Duval's eight assists came about six minutes into the game, when he poked the ball away from Mooney and dove toward the sideline to save it from going out of bounds. With his shoulders in the air above the sideline, Duval tossed the ball from his back up the floor to Bagley for a breakaway dunk.

Carter dunk, 8:12 remaining in the second half

Duke provided a clinic on how to break a press on this play, with all five players touching the ball during a possession that only lasted eight seconds and ended with a wide open dunk. Javin DeLaurier inbounded the ball to Goldwire, who took two dribbles before passing it up the middle back to DeLaurier. The sophomore quickly passed it across halfcourt to Duval, who took just two more dribbles before finding freshman Gary Trent Jr. on the baseline. Trent slipped it to Carter to cap the flawless sequence.

Looking forward

The Blue Devils will have one more tuneup against St. Francis Tuesday night and will still be looking for more defensive consistency before opening ACC play Saturday at Boston College. Duke only has four more games in the month of December and will have time to rest up and stay fresh before jumping back into a grueling schedule to start the spring semester.