Southern Miss (4-10, 1-2 Conference USA) shot over 48 percent, made 11 of 26 from beyond the arc and 18 of 21 free throws. Kourtlin Jackson scored 13 points with seven rebounds and Quinton Campbell added 11.
Old Dominion's Trey Freeman made a pair from the line to tie it at 60 with 2:32 to go. Southern Miss scored the next seven points - including Raheem Watts' 3-pointer - and then made 8 of 10 from the line for the win.
Southern Miss made six consecutive free throws at the end of the first half and led 34-31 at intermission.