The Bonnies (14-14, 7-8 Atlantic 10 Conference) have a one-game lead over the Dukes (15-14, 6-9) and George Washington in the conference, with one game apiece left. If St. Bonaventure holds on to finish eighth overall, it would host a first-round league tournament game.
Ogo Adegboye scored five points in an 11-0 run that put St. Bonaventure ahead 20-6 with 13:21 left in the first half. The Bonnies outshot Duquesne 56.0 percent (14-for-25) to 40.6 percent (13-for-32) in the half.
Duquesne got within 51-46 with 16:06 left, but St. Bonaventure rebuilt its lead to 67-54 with 11:55 left.
Michael Davenport added 17 points for the Bonnies.
Damien Saunders had 17 points and 13 rebounds, and Bill Clark 16 points, for Duquesne.