Smalley hit 8-12 field goals to lead the Tigers in scoring for a second straight contest.
The ninth-ranked Tigers used their height advantage to block 15 shots against the Dukes of the Atlantic 10 Conference, who fell to 9-4 with the loss.
The Tigers will take on host Miami at 6 p.m. CST on Tuesday at the BankUnited Center in the championship game of the tournament. The Hurricanes defeated Brown on Monday.
Five of Auburn's blocked shots came from 6-7 junior center Keke Carrier, who was 5-5 from the field and scored 11 points off the bench.
Senior guard Whitney Boddie scored 14 points and dished out three assists for the Tigers. Fellow senior DeWanna Bonner scored 13 points and pulled in 13 rebounds. Another senior, Sherrell Hobbs, also scored 13 giving the Tigers five scorers in double figures.
"That is a great thing when you get five players in double figures," Auburn coach Nell Fortner said. "We pushed the ball well, we were trying to attack the basket and Whitney Boddie really opened some things up for us and allowed to do some things today. That is what she does so well, she can draw defenses and she can score and I thought she was the most dangerous person on the floor today."
The Tigers shot 54.5 percent from the field and held the Dukes to 34.1 percent shooting. The Tigers finished with a 45-33 rebounding edge and made 11-15 free throws to 8-10 for Duquesne.
The Tigers turned the ball over 15 times, three more than the Dukes.
Auburn jumped to a quick 9-0 lead less than two minutes into the game and led 50-34 at halftime and were never seriously threatened.