Duke got all it could handle in its ACC opener.

The Blue Devils fell behind early against a hot-shooting Louisville team. They shot their second-worst 3-point clip of the season. And Cooper Flagg picked up his fourth foul with 10½ minutes left, exiting when Duke was down by five.

Duke won at Louisville 76-65 on Sunday night at the KFC Yum! Center.

It was the kind of performance — if the non-conference portion of the schedule didn’t already show it — that establishes Duke (7-2) as the frontrunner in the ACC.

Flagg picked up his fourth foul with 10:36 left and after Terrence Edwards Jr. made a couple of free throws made possible by Flagg’s foul, it was a 55-50 lead for Louisville.

That was apparently all No. 9 Duke needed to get going.

The Blue Devils went on an 18-2 run after Flagg’s exit. It started and ended with 3-pointers by Kon Knueppel, the freshman’s only two 3s of the game. Obviously, they came at good times.

Otherwise, Duke’s damage during this stretch came from the inside — a welcomed change for a team that made 8 of 30 3-pointers (26.7%). Sion James had a dunk and two free throws; all six of Maliq Brown’s points came within two minutes; and Tyrese Proctor hit a mid-range jumper.

By the time Flagg reentered, Duke’s lead was 68-60 with 4:42 left. The freshman scored 15 seconds later and helped Duke put away the game without Louisville (5-4) getting closer than seven of Duke’s lead for the rest of the game.

Flagg finished with 20 points and 12 rebounds; he fouled out in the final minute, the first time this season he’s exited with five fouls. Proctor had 13 points, Knueppel scored 12, and James finished with 11 points.

Brown was a star off the bench (again), with 11 rebounds, three steals and a block. Per usual, his total impact isn’t measured by stats — but his plus-minus was plus-24, the best in the game.

It’s the first time in Jon Scheyer’s three seasons Duke has won its first ACC road game. Two seasons ago, that meant a loss at Wake Forest; last year, it was a loss at Georgia Tech around this part of the calendar.

Another slow start was problematic for Duke and it had more to do with Louisville catching fire offensively than it had to do with what the Blue Devils were doing.

Louisville made eight of its first 11 3-point attempts — sizzling for anybody, but especially a team that entered the game making 27.3% of 3s (338th in the country). In four of Louisville’s last five games, the Cardinals made fewer than eight 3s.

The Cardinals missed their last five 3s of the first half, which is part of why Duke trimmed what was as large as a 14-point lead down to a 37-33 deficit at halftime. Louisville finished the game 11-for-31 on 3s; so the Cardinals were 3-for-20 to end the game.

The other part of Duke whittling that lead was forcing Louisville into turnovers — 10 of them in the first half, to put a number on it.

Those led to 14 of Duke’s points in the first half.

TIP-INS: Brown’s three field goals marked a season high for the Syracuse transfer. It’s the first time this season he’s had double-digit rebounds. … Louisville committed 15 turnovers; Duke only committed seven. … Edwards, the James Madison transfer, came off the bench and led Louisville with 21 points. … Duke outrebounded Louisville 21-13 in the second half. That came on the heels of Louisville holding a 21-14 advantage in the first half.