Duquesne had a 15-11 lead with 12:45 remaining in the first half before Xavier took over. The Musketeers ended the opening period on an 18-2 run and took a 45-26 lead at the break.
Reggie Jackson led Duquesne (16-9, 6-6) with 12 points. The Dukes hit just 30 percent of their shots from the field.
Xavier is 3 1/2 games in front of St. Joseph's and Temple in the race for the Atlantic 10 regular-season title.