The win raised Duquesne's record to 15-7, 6-3 in Atlantic 10 Conference play.
The Dukes led from that point till the final buzzer when the fans ran onto the court in celebration.
Senior Aaron Jackson paced the Dukes with 21 points, five rebounds, three assists and a steal against a single turnover. Clark tallied 18, hitting 6-of-7 and all four shots from beyond the arc.
Sophomore Damian Saunders, who fouled out with 1:55 left to go, had six rebounds, two assists, two steals, and a game-high three blocks.
Duquesne led by 14 at 26-12 with 11:28 to go in the first half and had a 45-30 lead at the break, making 17 of 21 from the floor.
Xavier cut the lead to 48-40 with 16:20 remaining. But Duquesne had an answer. Bolding's putback raised the Dukes' edge to 56-41 with 11:49 on the clock.
Xavier got to within three, 69-66, with 10 seconds to go. Duquesne made free throws down the stretch to preserve the win.
The Dukes are back in action on Wednesday, February 11, 2009, when they take on Richmond in the Spiders' Robins Center at 7:00 p.m.