The Blue Demons' press forced 27 turnovers in their second game in the Cancun Challenge.
Melvin, the 2010-11 Big East rookie of the year, was 11 of 18 from the field and grabbed eight rebounds. Moses Morgan added 15 points for DePaul (2-1).
Anthony Campbell led Austin Peay (1-2) with 17 points.
The Blue Demons shot 51.3 percent from the field and 9 of 23 from 3-point range. DePaul never trailed and built a 58-30 halftime lead.
DePaul took an 8-0 lead. The Governors pulled to within 10-9, but the Blue Devils went on a 22-4 run and Melvin's 3-pointer later extended the lead to 39-16 with 6:47 left before halftime. Young hit a layup to give DePaul a 30-point lead with 1:23 remaining.