Watch: Wayne Blackshear throws down impressive dunk vs. Duke
With under nine minutes remaining in the first half, Blackshear drove past Blue Devils guard Tyus Jones, cut into the lane and exploded for a one-handed jam.
The flush gave the Cardinals a three-point lead.
Over 17 games this season, Blackshear has averaged 12.5 points and 5.3 rebounds.
No. 6 Louisville entered Saturday at 15-2, while No. 4 Duke is 14-2 following consecutive losses to N.C. State and Miami.